Best F-Stop range to shoot between?

ChrisA said:
However I recently read that when James Longley shot the documentary Iraq In Fragments using a Dvx (then blown up to 35mm), he kept the iris wide open the whole time and used the Nd filters/ shutter speed to control exposure. (I think the theory being let as much light into the sensors as possible)
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I think Longley wanted to decrease his depth of field as much as possible and create a more cinematic-feeling image. I have to say that overall the film looked lovely, but in certain scenes, the use of a high shutter simply as a control over the exposure was a bit distracting.
 
Hey, Oedipax:

I totally agree on the Longley - Iraq - shutter deal. I'll admit that it was pretty trippy and cool at times. Especially when the music punched it up. Other times, it was jarring and semi-epileptic. Good film though - I just think switching shutter all the time like that would get old quick.
 
clumsy_cool said:
I don't know if there's another thread about this, but lets say your using a 35mm adapter, do you have to adjust both f-stops on the DVX lense and on the SLR lens that has been attached to reach optimal quality or do you just worry about the SLR lens.
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You certainly need to hit both lenses sweet spots. One reason I'm a bit skeptical of adapters at times has a lot to do with the fact that in order for you to get a very sharp image, you need both lenses at optimal f/stops, which means you have a very low sensitivity camera setup going on. This isn't a big issue when shooting outside, but for interiors, its quite a problem.
 
Hey could the softness in williams picture f1.6 also be due to the use of the ND filter? Anytime you add more glass you reduce image quality right?
 
It's certainly possible, but it depends on what type of glass your using too, keep in mind, the DVX isn't a super high res DSLR... I'm using a few Cokin optical resin filters with my Andromeda, and I can't see any sharpness issues whatsoever. The only sharpness issues I've seen caused by an optical resin filter has been with much higher res DSLRS, and even at that, you can only see it when you blow the image up to like 100%, and most DSLR images will never get that type of blow up... if yours do, you probably have the money to buy $200 filters.

One thing to to note however... is it the filter... or is it the lens? He is changing his f/stop to compensate, and its proven that f/stop changes can make an image softer... only way to be sure is to slap on an ND and use more light, not open the f/stop up more.
 
I'll see if I cannot do a test where I change the shutter speed instead of adding the ND filters. This should have no affect on the optical chain and should isolate the lens and how soft or sharp it becomes.
 
So far I've found that "50-60mm" range at f/5.6 is the sweet spot, you can get away with f/4 though, but any lower and you are just gonna get a softer image. I've also found you can shoot at f/2.8 just fine if you have the lens at its shortest focal length, if you shoot full telephoto, you will need a very small aperture of about f/8 to get optimal sharpness in all three channels. As you can probably see, there is a correlation going on here...
 
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