XDCAM and low light

[Serena Steuart]

Originally Posted by Brian Cassar

Thanks Serena for the technical reply. The problem is that I'm presently used to filming at very low light situations with an SD Sony camcorder (DSR-300) rated at F11 at 2000lux - and it does wonders. I know that SD and HD sensors differ but I'm just curious to know how much will I loose with a F10 at 2000 lux sensitivity? Will it be just one stop or could it be more?

f/11 is a 1/3 stop smaller than f/10 -- the same, in practice.

[Serena Steuart]

Originally Posted by Martin Mayer

Confused: is that "8 lux is good" statement supposed to be compared with the quoted "4 lux" rating given in the Z1 spec?

In fact given as 3 lux for the Z1, but I think that is much the same sort of figure as the 0.14 lux stated for the EX; 1/3 sec shutter, 18 dB gain, f/1.6
Generally the Z1 "speed" is rated about 250 ASA (0dB), whereas the EX is rated as 800 ASA at -3dB and looks to have a stop in reserve (in fact 2 stops from some shots seen at the roadshow). Rating the Z1 at 250 ASA, then at 1/60 sec shutter at f/1.6 it needs 175 lux (reading off my Lunasix meter).

Of course that is taking an incident light reading which is calibrated to be the same as reading of reflected light from an 18% grey card. So the actual equivalent figure is probably about 32 lux for the Z1.

[Bob Grant]

To really measure low light performance isn't exactly a trivial task, the quoted figures mean little without a S/N figure and even then there seems to be no agreed standard for how that is measured. I've seen (and shot myself) footage from some HDV cameras that it's claimed show 'acceptable' low light performance and yet to me looking at the amount of noise I have a problem considering it acceptable.
I think it also worth considering that Sony have been using a bit if digital magic in their recent camera such as level based dynamic noise reduction and that can have some undesirable side effects. So there's an even greater challenge with the EX1, not just getting a comparative set of figures against its peers but also checking for any unwanted artifacts when it's stressed.

[Stu Holmes]

From what i hear, the EX1 is a lot better in lowlight than a Z1.
Someone who is used to Z1s has played around with an EX1 and its a lot more sensitive for sure.

The specs at the NYC store are usually correct, but not always. In this case, i would suggest that the 4lux figure is an error. And as someone previously pointed out, the senstivity IS provided by manufacturer, which contradicts the NYC stores statement on their specs page.

[Steven Thomas]

Since the specs look decent and we're hearing from a couple hands-on review that it fairs well in low light, I'm willing to believe it's decent.

[Brian Cassar]

I've contacted B&H regarding this query. Their reply which was received a few minutes ago is as follows:

"SONY PMW EX1 specifications

from the Sony website

http://www.sonybiz.net/biz/view/Show...DCAMCamcorders

Sensitivity (2000 lx, 89.9% reflectance)
F10 (typical) (1920 x 1080/59.94i mode)

Minimum illumination
0.14 lx (typical) (1920 x 1080/59.94i mode, F1.9, +18 dB gain, with 64-frame accumulation)

S/N ratio
54 dB (Y) (typical)

from the B&H website

http://www.bhphotovideo.com/c/produc...AM_EX_SxS.html

Sensitivity Not Specified by Manufacturer

Minimum Illumination 4 Lux f1.6 at 18 dB

Vertical Smear Not Specified by Manufacturer

The way I read the specs the light sensativity of this camera is not very good.

The Sony site shows the the sensativity at F1.6
while the B&H site is showing the sensativity at 1.9

The bench mark for illumination camparison is taken at F11, the limitation of the camera lens and appeture do not allow that reading, so technically you would want to take the sensativity measurement at the highest stop.

The B&H website offers the specifications that are available at the time of the publishing of the webpage.

The specifications are offered as a convienience to our customers and should not be considered as control tested by B&H

It is always best to defer to the manufacturers website whenever possible

Just keep in mind that the manufacturers will offer the specs that make their products look the most desirable."

I admit I didn't really understand this reply. If the sensitivity is a standard benchmark (as opposed to the highly debatable lux ratings), than theoretically a sensitivity of F10 is very very good. As far as I know the best SD cameras have a sensitivity of F11. However having said that I'm not taking in consideration the S/N figure as Bob Grant has pointed out.

[Kevin Shaw]

I'd like to know exactly where B&H got the 4 lux figure because I don't see that number in Sony's literature, and B&H didn't state the sensitivity which is clearly listed in Sony's specifications. Looks to me like someone at B&H pulled a lux rating number out of thin air, and many people are quoting that instead of referencing what Sony says.

The Sony Z1U is widely rated at 3 lux and the EX1 rating should be lower than that; more likely around 1-2 lux.

P.S. According to the following review the EX1 is a hair more sensitive than the F330/F350 cameras: http://digitalcontentproducer.com/ca...ex/index2.html

[Steven Thomas]

What does B&H video have to do with real actual specs?
They are a store. They sell camera supplies.

If you're worried, you best bet is not to buy the camera until you can try it, or wait for more reviews.

So far the hands-on pre model review are positive for sensitivity.

[Adam Reuter]

I'd hate to break it to some of you HVX200 lovers out there but the camera IS NOT GOOD in low light. The frame grabs in the first post look very similar to tests I've done using 0 dB, 1/60, 1080/60i settings on the HVX200. While I love the Panasonic in every way, it requires a decent amount of light to look good. Anything over 6 dB of gain on that camera looks like garbage in HD. 1/3 inch chips just can't cut it at the moment for HD acquisition in low light.

The setup for the photo looks like a living room with no couch lighting. The only lighting is from that lamp and it's not pointed at the couch. If the Sony camera can do that good with little to no noise it will be a stellar camera. The Digital Content Producer magazine preview mentioned that it's a tad faster than the PDW-F330/F350 cameras in low light. Sensitivity of F10 at 2000 lux, whereas the PDW-F330/F350 are F11 at 2000 lux.

On a side note, I really hate how tests are conducted on independent sites. Those two pictures aren't worth the bandwidth used at 600pixels wide. Where are the full raster 1920x1080 pictures at? And then you have screen grabs that will be released when the camera comes out that people color corrected. BOO! Raw data please at practical settings. 24p at 1/24 shutter speed does not count (people were using this to show HVX200 sensitivity pics).

Let's use BitTorrent to host the jpeg files (or PNG files) if bandwidth limits are a concern!

If this camera lives up to the hype, Panasonic is making a huge mistake by not updating their chip for the next iteration of the HVX200. Or for that matter, not upgrading their LCD screen to HD.

[Serena Steuart]

Originally Posted by Kevin Shaw

I'd like to know exactly where B&H got the 4 lux figure because I don't see that number in Sony's literature,

The Sony Z1U is widely rated at 3 lux and the EX1 rating should be lower than that; more likely around 1-2 lux.

Let's keep up with the data here: Sony specifies the minimum illumination for the Z1 as 3 lux and the minimum illumination for the EX as 0.14 lux. What do these figures mean for people wanting to shoot in low light? Not much because those figures do not represent minimum illumination in normal video acquisition modes. The most useful figures to have in mind are 250 ASA (or ISO) and 800 ASA, the former being established in studio evaluations shooting under normal acquistion modes. This says the EX is about 2 stops more sensitive than the Z1. A conclusion reached some posts above by working at it from various directions.
How far can that be pushed on a particular shoot? Much depends on the scene (high key or low key) and mood. As Bob points out, the theoretical maximum speed may not be useful in a particular shoot.
The roadshow demonstrated latitude in the EX with a high key scene, which made it very difficult to see what was happening in the blacks (because there were hardly any) when pushed two stops. I think it safe to assume that at an ISO (ASA) of 3200 the EX will be noisy, although I couldn't see it in the corrected footage.

I'll add that my Canon EOS 5D starts to show noise at 1600 ISO and 800 is a good working maximum. That has a full 35mm frame sensor.

[Steven Thomas]

Originally Posted by Adam Reuter

If this camera lives up to the hype, Panasonic is making a huge mistake by not updating their chip for the next iteration of the HVX200. Or for that matter, not upgrading their LCD screen to HD.

I hear ya man.
The days of pixel shift are over. Give us a larger chip with native resolution!

[David Parks]

Rating at it 800 ASA -3db is excellent. I bet at 0db you could get by with 500
ASA or even 400 ASA, which is better than my HD 100 which can range from 100 to 325 on most shoots and lighting situations.

This certainly has enough latitude to do the job, Granted, I don't get stuck in low light situations much with my productions.

[Piotr Wozniacki]

To use a bit more practical assessment: one of expert Z1 users on another forum with lots of experience and expertise, after hands-on with the EX1, reported the low-light performance in a way suggesting that the camera actually brightens reality - just like the SD low-light champions (PD170) do. And without any undesirable side effects. I guess Stu Holmes had exactly the same person in mind when commenting a couple of posts ago in this thread.

This convinces me more than all those confusing and not precise enough figures.

[Serena Steuart]

Originally Posted by Piotr Wozniacki

To use a bit more practical assessment: the camera actually brightens reality . And without any undesirable side effects.

Excellent! Excellent! Today that's just what the world needs.

[Adam Reuter]

Originally Posted by David Parks

Rating at it 800 ASA -3db is excellent. I bet at 0db you could get by with 500
ASA or even 400 ASA, which is better than my HD 100 which can range from 100 to 325 on most shoots and lighting situations.

This certainly has enough latitude to do the job, Granted, I don't get stuck in low light situations much with my productions.

Actually, 0 dB would yield an even higher ASA rating, perhaps 1000 ASA? And if what Piotr Wozniacki says is true, that the EX1 "brightens reality" then this is JUST what I've been looking for in an HD camera in this price range since they were first introduced. That's the PD170/VX2100 look that event videographers NEED, not want....NEED!