Watch all other episodes of ON THE COUCH so far by clicking here!

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In the 23rd episode of ON THE COUCH, I was lucky enough to sit with fellow bloggers and shooters Dan Chung, Clinton Harn from newsshooter.com and Emmanuel Pampuri from pampuri.net.
In this second part of the talk, we focus on a subject that isn’t often talk about – long-term storage for data. As the discussion unfolds, it becomes clear that even professionals don’t follow a strict protocol when it comes to permanent archiving of projects that are finished.
Clinton surprises us by announcing that he ends up deleting some of the stuff he is shooting for projects to save storage space. Both he and Emmanuel use LTO tape drives for permanent backup, whereas Dan Chung and I currently still store everything on slower hard drives as soon as a project is done.
We also talk about how to access and actually find old projects in the stacks of hard drives and tapes that we stack in our offices. I recommend using NeoFinder, a neat little software that indexes everything from attached hard drives and can be set up to update the index automatically. When I look for something, I just enter a search query into NeoFinder and it shows me on which drive I can find the file. It also stores metadata of all files and even preview images and video clips if wanted.
In the 3rd part of this episode ON THE COUCH we look at SteadXP, an very exciting new stabilizer concept that follows a different path, because it’s a combination between a hardware box and software that interprets the movement in post production – Emmanuel Pampuri was involved with developing it and will introduce the technology. Stay tuned!
OTC-ep23-p2_Vimeo

 

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Please visit our sponsors’ websites to keep new episodes of ON THE COUCH coming! Thanks to G-Technology, Røde Microphones, Movidiam, FilmConvert & F&V.

The post Where to put old data for long term backup? – Dan Chung, Clinton Harn, Emmanuel Pampuri – ON THE COUCH, ep 23 part 2 (of 4) appeared first on cinema5D.

All credit is given to author cinema5D » NewsNino Leitner

Less than a year ago FotoDiox introduced a line of flat edge lit LED lights called the FlapJack. Using an array of LED lights that sit only at the surrounding edges and pointing inwards toward the center, the result is an extremely soft and diffused light source without hot spots or multi-shadow issues. At NAB 2015 they showed a number of new sizes and shapes to expand this line of LED lights.

You can find some of the original Flapjack lights over on their website, and hopefully the new larger sizes and shapes will be available soon. More information about the FlapJack LED lights can be found at the FotoDiox website (click here).

Fotodiox FlapJack Light LED ultra thin flat panel
find-price-button FotoDiox Ultra Thin FlapJack LED Video Light Panels

NAB 2015 Platinum Sponsors

All credit is given to author CheesyCamEmm

Comment on this article at the EOSHD Forum

Nikon D5100 raw video

Developer “leegong” of Nikon Hacker has made enormous progress in getting raw video from the live view function of the Nikon D5100. Early builds of the patch output raw frames to the card and A1ex of Magic Lantern has written a prototype / test DNG converter.

The raw video thread on the NikonHacker.com forums is hotting up and the forums are well worth keeping an eye on in the next few months.

One of the latest posts has a 1664 x 1102 12bit raw video frame converted to DNG by A1ex for download. Quality looks to be exceptional.

My understanding is that raw video on the D5100 will be 12bit.

Like Magic Lantern these frames are dumped as uncompressed data to the memory card from live-view on the DSLR. The .RAW files are then converted to an editable format in post like DNG.

Development effort into raw video on the D5100 has been going on for a few months but it’s only in the last few days that the breakthrough of actually getting a usable image from it has occurred.

Says developer “leegong” –

Ok , the most important core step for LV RAW hacking is coming:
just got chip4000 and chip6700 registers dumping for photo, photo defect and MV defect shooting,
photo and photo defect shoot 4992 x 3280 RAW and write it into RAM memory,
MV defect shoots 1664 x1100 RAW and writes it into RAM,
normal Liveview shoots LV RAW (i think it’s 1164 x 1100 which is same as MV defect RAW) but doesn’t write it into RAM,
just send it to chip4001 directly.
so we have to find out the difference of chip settings between these shooting modes,
then modify setting of normal LV so that LV RAW is written into RAM ,if this step is successful, it will be very easy to get LV RAW.

And then just a little later, we had the first image (processed to DNG with A1ex’s converter)…

d5100-raw-dng

Best of luck from the entire DSLR video community goes to Nikon Hacker!

Nikon shooters can support this effort by donating (top right of Nikon Hacker site here) and of course with testing / technical assistance on the forum.

Comment on the forum

The post Nikon Hacker enables raw video appeared first on EOSHD.

All credit is given to author EOSHDAndrew Reid (EOSHD)

Cinevate has announced a third update to it’s ever popular Duzi slider. Version 3 comes in two lengths, standard 24″ and a longer  32″ version. Solid carbon fibre rails increase it’s strength whilst maintaining a lightweight figure. But most importantly to current Duzi owners, a much improved lock!

The old lock was fiddly and only worked when the carriage was in the centre position. The revised version looks much more sturdy and allows use anywhere on the rail, love the look of this.

Solid carbon fibre rails means a 50% rise in payload, the Duzi now supports cameras up to 75lbs. As mentioned earlier, the Duzi v3 is available in 24″ and new longer 32″ length.

Here’s a full list of new features:

  • Updated brake to ensure a secure lock
  • Weight reduced for an even lighter slider
  • Bumpers on End Blocks for softer stops
  • Centre feet for increased strength and stability
  • Increased load capacity (75 lbs)

I’m a long term user of the Duzi, check out my review here. It’s weight and price makes it a very attractive tool and it still stands as my number 1 go to slider.

Available for pre-order right away, $50 separating each length.

The post Cinevate Duzi v3 Announced appeared first on cinema5D.

All credit is given to author cinema5D » NewsTim Fok

Even if your camera does not require a super fast media card to capture the highest quality video, there’s another reason why you might want faster speeds. After shooting a full day with three camera angles, you end up with quite a bit of footage. Downloading and backing up each media card can end up being a painfully slow process. If you can relate, then my suggestion is to make sure you have at least a Fast USB 3.0 Card Reader and combine that with faster recording media.

If you’re tired of waiting on transfer times, here’s a few excellent deals on Sandisk Media that ends this weekend (click here).

sandisk extreme pro sandisk extreme sdxc sandisk usb 3 card reader
find-price-button Sandisk Extreme SDXC, SDHC, Compact Flash, Card Readers

If you plan on storing this to an external drive, an external USB 3.0 drive is decent, but for the ultimate speed you should definitely look into some of the ThunderBolt Portable Drive Solutions. This will immediately make a noticeable difference at the end of the day when it comes to transferring that data over for backup.

Not to mention that the added benefit of Thunderbolt over USB 3.0, is that you can even playback and edit video over Thunderbolt much smoother than from a USB 3.0 drive.

Lacie ThunderboltThunderbolt portable USB driveWD Thunderbolt Raid 4TB
find-price-button Portable Thunderbolt External Hard Drives

All credit is given to author CheesyCamEmm

Even if your camera does not require a super fast media card to capture the highest quality video, there’s another reason why you might want faster speeds. After shooting a full day with three camera angles, you end up with quite a bit of footage. Downloading and backing up each media card can end up being a painfully slow process. If you can relate, then my suggestion is to make sure you have at least a Fast USB 3.0 Card Reader and combine that with faster recording media.

If you’re tired of waiting on transfer times, here’s a few excellent deals on Sandisk Media that ends this weekend (click here).

sandisk extreme pro sandisk extreme sdxc sandisk usb 3 card reader
find-price-button Sandisk Extreme SDXC, SDHC, Compact Flash, Card Readers

If you plan on storing this to an external drive, an external USB 3.0 drive is decent, but for the ultimate speed you should definitely look into some of the ThunderBolt Portable Drive Solutions. This will immediately make a noticeable difference at the end of the day when it comes to transferring that data over for backup.

Not to mention that the added benefit of Thunderbolt over USB 3.0, is that you can even playback and edit video over Thunderbolt much smoother than from a USB 3.0 drive.

Lacie ThunderboltThunderbolt portable USB driveWD Thunderbolt Raid 4TB
find-price-button Portable Thunderbolt External Hard Drives

All credit is given to author CheesyCamEmm

The RodeLink Wireless Filmmakers Kit has been a highly anticipated product for those looking for an affordable wireless mic system. Today they’ve officially announced the units will be shipping to authorized dealers worldwide!

The RodeLink is consistently monitoring and hopping between frequencies to maintain the strongest possible signal level at a range of up to 100 metres (over 100 yards). The RODELink is so intuitive that it works straight out of the box, with no channel selection necessary. For users with multiple RØDELink devices the system offers eight discrete channels that can be setup in seconds.

Power & Secure
Using a series II 2.4GHz encrypted digital transmission that is sent on two channels simultaneously, RODELink automatically selects the strongest signal and ensures your audio is as reliable and secure as a cabled connection.

(Click here for this Audio TIP)
audio setup a7s zoom h6 redundant
Setup for (3) Wireless G3 Mic Kits on Zoom H6 each with an attenuated Backup Audio Track

Because i’m using a technique that allows me to have an attenuated backup audio track for every person I mic up, I’ve been seriously looking into adding a few more wireless systems to my arsenal. I haven’t found solid results in anything under $700 bucks, so I’m hoping the RodeLink kit really delivers as they say. Remember they begin shipping units out to retailers today worldwide.

I’ve seen retailers announce a list price of $599, but are currently listing pre-orders right now for just $399 (found here).

Rode Wireless FIlmmaker Kit
find-price-button Rode Wireless Filmmaker Kit – Wireless Lav Mic System

All credit is given to author CheesyCamEmm

NAB 2015 – SHAPE gives us a tour of their new cage system for the Atomos Shogun Monitor + Recorder.

The optional monitor mount may seem like a small addition, but if you’ve ever had to work with friction arms on a large monitor, their 15mm monitor mount is the way to go. The design allows you to both swivel and tilt the monitor using SHAPE’s patented push button technology.

shape adjustable 15mm mount bracket
SHAPE Adjustable 15mm Mount Bracket

The ATOMOS SHOGUN CAGE from SHAPE is CNC machined from aluminum. Designed to protect while offering up attachment options using the surrounding 3/8″ and 1/4″ taps. Includes black knobs for the HDMI lock, and can be mounted on and optional adjustable 15mm monitor bracket. Optional handles can also be added to the SHAPE Shogun Cage to be used as a director’s monitor.

More information about the SHAPE Atomos Shogun Cage and accessories can be found at the website SHAPEWLB.com (HERE).

Shape Atomos Shogun Cage
find-price-button SHAPE Atomos Shogun Cage System

All credit is given to author CheesyCamEmm

kuulapaa 500 sw

Let’s face it, slow motion is bad ass. You don’t get more bad ass than this amazing shot of a .500 S&W Magnum by Herra Kuulapaa (www.kuulapaa.com). While this may be an extreme example, and it’s a still, not a grab from motion, nothing gets the imagination going quite like the ability to shoot high frame rates.

Give yourself the edge by understanding the fundamentals of global vs rolling shutter, shutter angles and exposures at high frame rates.

A few weeks back I wrote an article 8 Essential Steps to Perfect Exposure – The Knowledge Any Cameraman Should Have. If you haven’t read it yet, now would be a good time to do that, and then come back to read this one.

1. Mechanical Shutter

Moviecam_schematic_animationIn a film camera, the shutter is a mechanical rotating mirror. As it rotates 360 degrees per exposure it alternates covering and uncovering the film gate for a particular amount of time. The RPM of the shutter is mechanically fixed and determined by the frame rate, and the exposure time is determined by the shutter angle.

During exposure the film is held perfectly still, often with registration pins. While the mirror shutter covers the film gate, the pins mechanically disengage and the pull down claw physically advances the film to the next unexposed frame.

2. Rolling Shutter

A mechanical rotating shutter is effectively a rolling shutter. The frame is exposed gradually (albeit very quickly) from top to bottom as the edge of the shutter travels across the film.

Many electronic shutters in digital cinema cameras also feature a rolling shutter, where data is read out line by line from the top of the sensor to the bottom before being reset ready for the next frame exposure.

A rolling shutter can exhibit a noticeable skew of would-be vertical lines in the image if either the camera or subject is moving quickly across the frame. This can create unwanted motion artifacts warping the whole image if the sensor read-out is particularly slow and there is fast motion in the frame. Most rolling shutters are incredibly fast, minimizing potential problems. Red and Arri employ rolling shutters, and the results can lend a more “cinematic” feel than a global shutter.

Even extremely high frame rate cameras such as the Phantom digital cinema cameras from Vision Research employ rolling shutter, but with a read-out time of only 1 millisecond.

In this chart you can compare rolling shutter readout-times of different camera models we tested in our lab:

Test-Scores_RS_FS7

3. Global Shutter

A global shutter differs from a rolling shutter in that at the end of a full exposure, light is blocked entirely across the sensor all at once while data is then read and it is reset for the next exposure.

A global shutter preserves the perfect vertical alignment of vertical lines or objects moving horizontally through the frame. However, the feel of motion can be noticeably different from what would be captured even on film by a film camera.

Depending on how a global shutter is implemented, there can be a small cost in light (fill factor) and possibly dynamic range when compared to a rolling shutter.

4. Shutter Angle

shuttersShutter angle is a term that refers to the actual physical angle of the opening in a rotating mechanical shutter in degrees. The angle of the opening determines the duration of the exposure as the shutter rotates.

Mechanical shutters for the most part are gone in digital cinema cameras, but often the terminology has stuck.

Shutter angle is the same as your exposure time, and it is primarily how you control motion blur. The longer the exposure, the more motion blur, the shorter the exposure, the sharper any moving objects will appear.

It can be calculated easily to a fraction of a second exposure time.

Exposure time (1/x sec) = Frame Rate x (360 / Shutter Angle)

For example, at a frame rate of 24fps at 180 degree shutter (180 degrees is considered normal):

180 degrees: 24 x (360 / 180) = 1/48th second

Here is a whole table calculated for 24fps for shutter angles up to 220 degrees:

15 degrees = 1/576 sec
20 degrees = 1/432 sec
40 degrees = 1/216 sec
60 degrees = 1/144 sec
80 degrees = 1/108 sec
100 degrees = 1/86 sec
120 degrees = 1/72 sec
140 degrees = 1/62 sec
160 degrees = 1/54 sec
180 degrees = 1/48 sec
200 degrees = 1/43 sec
220 degrees = 1/39 sec

Any change in shutter angle changes the exposure time, and will need to be compensated for with a change in aperture to maintain correct exposure. Of course a change in aperture will affect depth of field. So if depth of field needs to remain unaffected also, the only thing left is to add ND filters (if reducing light to compensate for a longer exposure time) or increase the actual light levels illuminating the scene (if compensating for a shorter exposure time).

If we consider 180 degrees as the base (normal) angle as “Full Exposure”, the following compensation table applies.

Shutter Angle            F-Stop/T-Stop Compensation

197-200                     Close 1/4
166-196                     Full Exposure
148-165                     Open 1/4
135-147                     Open 1/3
121-134                     Open 1/2
111-120                     Open 2/3
99-110                       Open 3/4
83-98                         Open 1
74-82                         Open 1 1/4
68-73                         Open 1 1/3
61-67                         Open 1 1/2
56-60                         Open 1 2/3
50-55                         Open 1 3/4
42-49                         Open 2
37-41                         Open 2 1/4
34-36                         Open 2 1/3
31-33                         Open 2 1/2
28-30                         Open 2 2/3
25-27                         Open 2 3/4
22.5-24                      Open 3

5. High Frame Rates

Glock_HS

highspeed sea froth
In the age of digital cinema, more than ever before there is a demand for high frame rates in our cameras. This used to be a specialty requirement but is now expected.

Capturing the spray of ocean waves in crisp frozen detail, liquids pouring or simply the beauty of smooth slow motion is no longer out of our reach. Many cinema cameras can now shoot at least 60fps if not much higher.

Vision Research has been on top of extreme high speed cinematography for some time. While 1000 – 2000fps is still out of reach for most of us, cameras like the Phantom Flex 4K are pushing the limits of what can be achieved.

Be aware of how high frame rates impact your exposure (and light requirements).

Alexa Menu HSFor any camera, regardless of sensor, regardless of manufacturer the same rules are true when it comes to high frame rates and exposure. It’s purely mathematics.

Every time you double the frame rate, you are halving the exposure time for each frame… and halving the amount of light hitting the sensor.

For an example, lets assume a “normal” shutter angle of 180 degrees.

At 24 frames per second, with a 180 degree shutter gives us an exposure time of 1/48th sec.

If we double the frame rate to 48fps, with the same shutter angle we halve the exposure time to 1/96th sec. We’ve just lost a full stop of light and are only at 48fps.

Let’s extrapolate this out and I’ll rather use 25fps as a starting point instead of 24fps because it will multiply out with round numbers:

25fps @ 180deg = 1/50th sec
50fps @ 180deg = 1/100th sec (1 stop loss)
100fps @ 180deg = 1/200th sec (2 stop loss)
200fps @ 180deg = 1/400th sec (3 stop loss)
400fps @ 180deg = 1/800th sec (4 stop loss)

Of course frame rates can be anywhere in between these numbers but I’ve simply doubled it every time for the example.

So you can see we’re losing a stop of light every time we double the frame rate.

Losing a full stop is not a small amount of light. Every stop lost is a halving of light.

1 stop loss = 1/2 the light
2 stop loss = 1/4 the light
3 stop loss = 1/8 the light
4 stop loss = 1/16 the light

Just as a change in shutter angle at a normal frame rate affects exposure time and requires a compensation to be made in lens aperture or lighting, high frame rates require even more compensation beyond just opening up the lens.

This means if you have enough light for a correct exposure at 25fps, you’ll have to double the amount of light used to light your scene or subject to get the same correct exposure at 50fps.

You’ll have to quadruple the amount of light on your subject to have a correct exposure at 100fps. This just doubles every time, so to have a correctly exposed image at 200fps you need 8x the amount of light on your scene as you would at a normal 25fps frame rate.

The sun gives us plenty of light for this, so outside under daylight, compensating for the much shorter exposure times when shooting high frame rates is much less of an issue.

However, inside under artificial lighting… you have to crank up the light seriously (double it) every time you double the frame rate.

It’s normal that high speed table top shoots for instance require a ton of light. If you are on set when shooting a product shot involving a liquid pouring and they have a Phantom on set shooting at 1000fps, they will have serious light on that product.

6. Base Sensitivity

When it comes to high frame rates, a higher “native” base ISO or exposure index (EI) is always beneficial. Keep this in mind when comparing cameras. Every sensor is different and every camera will perform differently capturing high frame rates.

If a particular camera gives brighter images at high frame rates, it’s either because the sensor has a higher base ISO (down to different photosite size or layout or some improvement at the semiconductor level), or it can be pushed above it’s base ISO with acceptable noise (again… could be down to the sensor, or just some clever noise reduction processing).

Base sensitivity of a sensor is down to many things, simplest of which is the size of the photosites (but that is a huge over simplification), and this is affected basically by how many of them are crammed onto the sensor. If you increase resolution (or number of photosites) and keep sensor size the same, the photosites get smaller and as a gross generalization, base sensitivity will decrease.

The amount of space between photosites is also a factor, and the amount of space needed for circuitry at each photosite.

7. Shot Noise

In the end regardless of all this there is “shot noise”, a minimum level of “noise” when counting or detecting small numbers of photons that is due to variations in quantum probability. If you throw one single photon at a 50% grey surface, there is a 50% probability that it will be reflected or absorbed. So that surface could show up if the photon is reflected and detected at a photosite, or it could be black if the photon is absorbed rather than reflected.

The more photons that are thrown at the 50% grey card, eventually probability dictates that 50% will be reflected and 50% will be absorbed. If you flip a single coin, it will land either heads, or tails but there can only be one possible outcome and the probability is equal it could land either way. If you flip 1000 coins, you should on average count 50% heads and 50% tails.

I don’t want to over-play “shot noise”, it’s only a factor at extremely low light levels, but I just want to point out that even if an image sensor is otherwise perfect (which none are), it does define a impenetrable minimum noise floor that is simply down to quantum physics.

8. Light

A image sensor will always perform best when there is plenty of light, and when you have very short exposure times for each frame (as in pushing higher frame rates) the only solution is more light.

As I have explained before in 8 Essential Steps to Perfect Exposure – The Knowledge Any Cameraman Should Have exposing your sensor properly is the single most important key to achieving the image you envision seeing beautifully graded and finished after post production.

The post 8 Essential Steps to Understanding Global vs Rolling Shutter and High Frame Rates appeared first on cinema5D.

All credit is given to author cinema5D » NewsRichard Lackey

kuulapaa 500 sw

Let’s face it, slow motion is bad ass. You don’t get more bad ass than this amazing shot of a .500 S&W Magnum by Herra Kuulapaa (www.kuulapaa.com). While this may be an extreme example, and it’s a still, not a grab from motion, nothing gets the imagination going quite like the ability to shoot high frame rates.

Give yourself the edge by understanding the fundamentals of global vs rolling shutter, shutter angles and exposures at high frame rates.

A few weeks back I wrote an article 8 Essential Steps to Perfect Exposure – The Knowledge Any Cameraman Should Have. If you haven’t read it yet, now would be a good time to do that, and then come back to read this one.

1. Mechanical Shutter

Moviecam_schematic_animationIn a film camera, the shutter is a mechanical rotating mirror. As it rotates 360 degrees per exposure it alternates covering and uncovering the film gate for a particular amount of time. The RPM of the shutter is mechanically fixed and determined by the frame rate, and the exposure time is determined by the shutter angle.

During exposure the film is held perfectly still, often with registration pins. While the mirror shutter covers the film gate, the pins mechanically disengage and the pull down claw physically advances the film to the next unexposed frame.

2. Rolling Shutter

A mechanical rotating shutter is effectively a rolling shutter. The frame is exposed gradually (albeit very quickly) from top to bottom as the edge of the shutter travels across the film.

Many electronic shutters in digital cinema cameras also feature a rolling shutter, where data is read out line by line from the top of the sensor to the bottom before being reset ready for the next frame exposure.

A rolling shutter can exhibit a noticeable skew of would-be vertical lines in the image if either the camera or subject is moving quickly across the frame. This can create unwanted motion artifacts warping the whole image if the sensor read-out is particularly slow and there is fast motion in the frame. Most rolling shutters are incredibly fast, minimizing potential problems. Red and Arri employ rolling shutters, and the results can lend a more “cinematic” feel than a global shutter.

Even extremely high frame rate cameras such as the Phantom digital cinema cameras from Vision Research employ rolling shutter, but with a read-out time of only 1 millisecond.

In this chart you can compare rolling shutter readout-times of different camera models we tested in our lab:

Test-Scores_RS_FS7

3. Global Shutter

A global shutter differs from a rolling shutter in that at the end of a full exposure, light is blocked entirely across the sensor all at once while data is then read and it is reset for the next exposure.

A global shutter preserves the perfect vertical alignment of vertical lines or objects moving horizontally through the frame. However, the feel of motion can be noticeably different from what would be captured even on film by a film camera.

Depending on how a global shutter is implemented, there can be a small cost in light (fill factor) and possibly dynamic range when compared to a rolling shutter.

4. Shutter Angle

shuttersShutter angle is a term that refers to the actual physical angle of the opening in a rotating mechanical shutter in degrees. The angle of the opening determines the duration of the exposure as the shutter rotates.

Mechanical shutters for the most part are gone in digital cinema cameras, but often the terminology has stuck.

Shutter angle is the same as your exposure time, and it is primarily how you control motion blur. The longer the exposure, the more motion blur, the shorter the exposure, the sharper any moving objects will appear.

It can be calculated easily to a fraction of a second exposure time.

Exposure time (1/x sec) = Frame Rate x (360 / Shutter Angle)

For example, at a frame rate of 24fps at 180 degree shutter (180 degrees is considered normal):

180 degrees: 24 x (360 / 180) = 1/48th second

Here is a whole table calculated for 24fps for shutter angles up to 220 degrees:

15 degrees = 1/576 sec
20 degrees = 1/432 sec
40 degrees = 1/216 sec
60 degrees = 1/144 sec
80 degrees = 1/108 sec
100 degrees = 1/86 sec
120 degrees = 1/72 sec
140 degrees = 1/62 sec
160 degrees = 1/54 sec
180 degrees = 1/48 sec
200 degrees = 1/43 sec
220 degrees = 1/39 sec

Any change in shutter angle changes the exposure time, and will need to be compensated for with a change in aperture to maintain correct exposure. Of course a change in aperture will affect depth of field. So if depth of field needs to remain unaffected also, the only thing left is to add ND filters (if reducing light to compensate for a longer exposure time) or increase the actual light levels illuminating the scene (if compensating for a shorter exposure time).

If we consider 180 degrees as the base (normal) angle as “Full Exposure”, the following compensation table applies.

Shutter Angle            F-Stop/T-Stop Compensation

197-200                     Close 1/4
166-196                     Full Exposure
148-165                     Open 1/4
135-147                     Open 1/3
121-134                     Open 1/2
111-120                     Open 2/3
99-110                       Open 3/4
83-98                         Open 1
74-82                         Open 1 1/4
68-73                         Open 1 1/3
61-67                         Open 1 1/2
56-60                         Open 1 2/3
50-55                         Open 1 3/4
42-49                         Open 2
37-41                         Open 2 1/4
34-36                         Open 2 1/3
31-33                         Open 2 1/2
28-30                         Open 2 2/3
25-27                         Open 2 3/4
22.5-24                      Open 3

5. High Frame Rates

Glock_HS

highspeed sea froth
In the age of digital cinema, more than ever before there is a demand for high frame rates in our cameras. This used to be a specialty requirement but is now expected.

Capturing the spray of ocean waves in crisp frozen detail, liquids pouring or simply the beauty of smooth slow motion is no longer out of our reach. Many cinema cameras can now shoot at least 60fps if not much higher.

Vision Research has been on top of extreme high speed cinematography for some time. While 1000 – 2000fps is still out of reach for most of us, cameras like the Phantom Flex 4K are pushing the limits of what can be achieved.

Be aware of how high frame rates impact your exposure (and light requirements).

Alexa Menu HSFor any camera, regardless of sensor, regardless of manufacturer the same rules are true when it comes to high frame rates and exposure. It’s purely mathematics.

Every time you double the frame rate, you are halving the exposure time for each frame… and halving the amount of light hitting the sensor.

For an example, lets assume a “normal” shutter angle of 180 degrees.

At 24 frames per second, with a 180 degree shutter gives us an exposure time of 1/48th sec.

If we double the frame rate to 48fps, with the same shutter angle we halve the exposure time to 1/96th sec. We’ve just lost a full stop of light and are only at 48fps.

Let’s extrapolate this out and I’ll rather use 25fps as a starting point instead of 24fps because it will multiply out with round numbers:

25fps @ 180deg = 1/50th sec
50fps @ 180deg = 1/100th sec (1 stop loss)
100fps @ 180deg = 1/200th sec (2 stop loss)
200fps @ 180deg = 1/400th sec (3 stop loss)
400fps @ 180deg = 1/800th sec (4 stop loss)

Of course frame rates can be anywhere in between these numbers but I’ve simply doubled it every time for the example.

So you can see we’re losing a stop of light every time we double the frame rate.

Losing a full stop is not a small amount of light. Every stop lost is a halving of light.

1 stop loss = 1/2 the light
2 stop loss = 1/4 the light
3 stop loss = 1/8 the light
4 stop loss = 1/16 the light

Just as a change in shutter angle at a normal frame rate affects exposure time and requires a compensation to be made in lens aperture or lighting, high frame rates require even more compensation beyond just opening up the lens.

This means if you have enough light for a correct exposure at 25fps, you’ll have to double the amount of light used to light your scene or subject to get the same correct exposure at 50fps.

You’ll have to quadruple the amount of light on your subject to have a correct exposure at 100fps. This just doubles every time, so to have a correctly exposed image at 200fps you need 8x the amount of light on your scene as you would at a normal 25fps frame rate.

The sun gives us plenty of light for this, so outside under daylight, compensating for the much shorter exposure times when shooting high frame rates is much less of an issue.

However, inside under artificial lighting… you have to crank up the light seriously (double it) every time you double the frame rate.

It’s normal that high speed table top shoots for instance require a ton of light. If you are on set when shooting a product shot involving a liquid pouring and they have a Phantom on set shooting at 1000fps, they will have serious light on that product.

6. Base Sensitivity

When it comes to high frame rates, a higher “native” base ISO or exposure index (EI) is always beneficial. Keep this in mind when comparing cameras. Every sensor is different and every camera will perform differently capturing high frame rates.

If a particular camera gives brighter images at high frame rates, it’s either because the sensor has a higher base ISO (down to different photosite size or layout or some improvement at the semiconductor level), or it can be pushed above it’s base ISO with acceptable noise (again… could be down to the sensor, or just some clever noise reduction processing).

Base sensitivity of a sensor is down to many things, simplest of which is the size of the photosites (but that is a huge over simplification), and this is affected basically by how many of them are crammed onto the sensor. If you increase resolution (or number of photosites) and keep sensor size the same, the photosites get smaller and as a gross generalization, base sensitivity will decrease.

The amount of space between photosites is also a factor, and the amount of space needed for circuitry at each photosite.

7. Shot Noise

In the end regardless of all this there is “shot noise”, a minimum level of “noise” when counting or detecting small numbers of photons that is due to variations in quantum probability. If you throw one single photon at a 50% grey surface, there is a 50% probability that it will be reflected or absorbed. So that surface could show up if the photon is reflected and detected at a photosite, or it could be black if the photon is absorbed rather than reflected.

The more photons that are thrown at the 50% grey card, eventually probability dictates that 50% will be reflected and 50% will be absorbed. If you flip a single coin, it will land either heads, or tails but there can only be one possible outcome and the probability is equal it could land either way. If you flip 1000 coins, you should on average count 50% heads and 50% tails.

I don’t want to over-play “shot noise”, it’s only a factor at extremely low light levels, but I just want to point out that even if an image sensor is otherwise perfect (which none are), it does define a impenetrable minimum noise floor that is simply down to quantum physics.

8. Light

A image sensor will always perform best when there is plenty of light, and when you have very short exposure times for each frame (as in pushing higher frame rates) the only solution is more light.

As I have explained before in 8 Essential Steps to Perfect Exposure – The Knowledge Any Cameraman Should Have exposing your sensor properly is the single most important key to achieving the image you envision seeing beautifully graded and finished after post production.

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All credit is given to author cinema5D » NewsRichard Lackey