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technical trouble


craigbuckley

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I was wondering if anyone could point out a good link to read about shooting with the sharpest aperture. I shot a concert last night and the footage looks ok. I ran into two problems.

One- there were white pieces of paper on the wall that gave off a bright white glare that I tried to reduce by lowering iso and fiddling with the aperture, but this made the band's faces too dark so I had to leave the bright white area in the shot. How would you have dealt wi th this?

Two- I always thought having the widest aperture would give you the sharpest shot but I've been reading that's not true. Some people say F 8 is the sharpest point of the aperture but doesn't it depend on the lens? if someone could just point me in the right direction to learn about this that would be great.
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I can't think of the technical term for the problem you're having with the white paper but it is to do with both your lens (some lenses have a "glare" when dealing with strong light and using a wide aperture) but it also could have just been that you were blowing it out (making that specific part of the image over exposed) as you were exposing for the band. Blowing out highlights is just something everyone has to deal with when dealing high contrast situations (like if it's a very very bright day and you are trying to film/photograph someone in dark shade you might blow out the sky making it white instead of blue). With practice you will learn how to better deal with these situations better but sometimes there is no way around it. This comes down to "Dynamic Range" if a camera has better Dynamic range it will handle high contrast situations.. This is one area where film is still superior to digital.

 

The peak performance of a lens is usually around f/5.6 or f/8.. When a lens is "wide open" shooting at its widest aperture (f/1.8, f/1.4 f/1.2 etc) unless it's extremely good will usually be slightly softer than when it's at f/5.6 or f/8.. However, stopping all the way down to f/22 doesn't make your pictures any sharper it actually makes them worse due to lens diffraction (look it up) lens diffraction will appear at different apertures (dependent on sensor size).

 

I'm honestly not sure how noticeable lens diffraction is for video but any good photographer will avoid shooting at such apertures as it will make your images softer. Good luck.

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One- there were white pieces of paper on the wall that gave off a bright white glare that I tried to reduce by lowering iso and fiddling with the aperture, but this made the band's faces too dark so I had to leave the bright white area in the shot. How would you have dealt wi th this?

I had the same thing with the GH2 once with a fast non-MFT-lens, a Nikon 50mm f1.4. Every light produced a glow, and the whole image was too soft (not seen on the Sony Monitor I had attached via HDMI). My mistake: I didn't make night-testshots in advance. I did later and found, that the lens was only usable @f2.0 and further. You should have closed the aperture one stop and increase the iso instead.

Gig.jpg

Two- I always thought having the widest aperture would give you the sharpest shot but I've been reading that's not true. Some people say F 8 is the sharpest point of the aperture but doesn't it depend on the lens? if someone could just point me in the right direction to learn about this that would be great.

Very fast lenses tend to produce softer images at wide open. The best sharpness for MFT seems to be 3.5 or 4. At f8, the DOF gets deeper, of course, but details may be lost. It depends, as you say, on the lens. Tests are needed to know for sure.

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Ok wow thanks a lot guys. Thats exactly what I needed, and that makes much more sense. I'm a dumb ass. I had the impression that when filming with a DSLR you should always have the aperture as wide as possible (unless too bright out) and the ISO as low as possible, for the best quality image. I was wrong, right?

 

Any good suggestions to read up on something like this? I have been reading about aperture in photography. I understand how with the widest aperture on a lens a very small part of the image would be in sharp focus, and that there is a sweet spot in the middle of aperture spectrum. I just am wondering how to figure this out for my lenses, because I don't know if my eyes can tell.. and I am definitely going to start shooting a lot more and doing more tests.

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@gravitatemediagroup
Wouldn't you only use a variable ND outdoors?


@craigbuckley
Did you know the band? Did you have access to the stage before they played?
Would it have been possible to remove the white pieces of paper from the wall?
Or could you have moved your camera to avoid shooting the white pieces of paper?
I think you learnt quite a bit from this about the dynamic range of the camera.
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DefInItely. I will put up some screen shots later but I didn't have access to the stage before. It happened quick and I tried to avoid the white paper but the band was right next to it. I have the setting on my gh 2 where it flashes in the area where there's white spots. I messed around with the aperture/iso but whenever I made the white spots less bright the band would be too dark, and when I tried to make the band less dark the white paper got too bright. It was brutal, I chose to keep it overly brig ht and hopefully fix it in color correction.


But as far as sharpness goes, say on my slr magic nokton 12mm, what would be the sharpest point of the aperture? It's hard to see what's sharp at the moment when I'm filming with the LCD or evf screen.
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