low light performance - any better than DSLR's?

T

tikigod19

Well-known member
Hi all,

I'm gradually working through my check list and finding the right camera to compliment the AF100. Wanting a DSLR (as I di a bit of photography as well) I've got it down to 60d, 7d and 5d mkii however, having never used a DSLR for video I have fears about low light performance.

For example if I had a 2.8 zoom or a 1.8 prime just how low could the light go on any of the above cameras (obviously the AF100 included) before the ISO grain is noticeably visible.

I currently have sony HDR-FX1's and in dark wedding speech scenarios at full zoom I need to resort to up to 15 or sometimes 18gb of gain. Would this be the equivalent of a certain ISO value or is 3200ISO on a AF100 still well below that of 18gb gain on the FX1?

I know the best thing to do is to test test test but seeing as I dont have any of these cameras yet this is not possible.

I'm worried that if I need to set the aperture to 5.6 in darkish conditions in order to get a decent DOF, I will need such a high ISO that I'll regret my choice to switch to interchangeable lens video...
 
The iris and the cleanness of the ISO are two separate subjects.
Most folks seem to think that the limit on a DSLR is about 640 to 800 before the grain gets to be too much for their taste. That puts them at about two to 2.5 stops faster than an FX1 already, as the FX1 is (IIRC) about 160 ISO. When you put it on 15dB of gain, you're adding 2.5 stops worth of brightness to it, which just brings it up to 800 ISO equivalent in that case. And I would bet that the DSLR has a lot less grain than the FX1 at 15dB. So as long as you set the iris comparable to what the FX1's iris is, you should be in pretty good shape. If the FX1 is running at f/2.8 and you try to put an f/5.6 lens on the AF100, well, you're gonna have problems, of course, but if you can match the iris and put f/2.8 on the AF100, you should be happier with the resulting pictures.
 
thanks very much Barry. I did some tests last night with the GH1 which I'd assume is similar to the AF100 in low light? With the 20mm 1.7 I have no problems at all. I only have the kit zoom so and that was near useless but when I get the AF100 I'll have a constant 2.8 zoom on it which I think will be just about ok with a bit of an ISO nudge. The things I'll be filming in low light will be more of a 'I have to get them on film' rather than 'it has to be the crispest quality on the entire production' type of shot so pushing ISO up a bit if necessary doesn't worry me.

I noticed the GH1 is limited to 1600 iso but I believe I read the AF100 can go to 3200 (or was it 6400)?

Does anyone have an idea what the max ISO for video recording on the canon 5d ii, 7d and 60d is by comparison?
 
The AF100 is better than the GH1. It's a bit more sensitive, and all the gleck in the GH1's image is cleaned up in the AF100 (no vertical streaking, etc). You can push the AF100 to 3200 ISO, but I wouldn't. I think 800 is a reasonable upper limit, and 1600 when necessary. 3200 is for extreme cases.
 
Yes the hacked GH1 is amazing at full data rate in good light, but the low light performace in the dark areas of a picture is pretty horrendous and can benefit from a subtle de-noise filter in post. I would expect the AF100 to be a lot better.
 
to be honest I've never recorded any low light footage on my GH1, only looked through the viewfinder when testing regarding this post. I might get it out tonight and actually edit some footage to see the issue.
 
The GH1 does have some grain and streaking (fixed pattern noise) at 1600 but weddings are an extreme case. Even with the noise the picture quality of the GH1 at 1600 paired with fast glass (an old Canon,Nikon,Minolta,Pentax, whatever 50mm f1.8 or Panasonic's pancake 20mm f/1.7) is no where near as noisy as a 1/3 inch videocamera at 12db gain. At most weddings i use my HMC150 for the ceremony and at the reception it stays in the camera bag. Most folks who talk about the camera getting too noisy to use are coming from work where they could control the lighting and have a different (and understandably so) definition of "too Noisy"

Low light performance of the GH1 is in a different leage from the traditional wedding prosumer cameras as long as you put fast glass in front of it. the canons are even better in low light than the GH1 but i dont want the 12min record time restriction.
 
tikigod19 said:
John,
Do you think even the crop canons like 7d or 60d are better than gh1 in low light?
Click to expand...

someone else might be able to better answer that but i suspect that they are probably like a stop faster or so. Barry Green put a great comparison article in the article section of the main page but im pretty sure he did that before the T2i or the 60D.
 
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