Bart,
What about the choice of lens with the 5DII. If I use an EF 50 1.4 v. the 50 1.2 at f4 or f5.6 is there likely to be a difference in DR.
Hi Asher,
That's hard to say without testing for the lighting conditions it is going to be used in. So, for the moment I can only look at generic MTF curves and they suggest that the 1.4 may be a bit more contrasty at these medium apertures. I do recall reading that the f/1.2 has good glare resistance, but I haven't tested that myself.
In any case, it is important to use a properly dimensioned lenshood, because
any stray light entering the lens that is not going to add to the image forming itself,
will deteriorate the image quality. The first thing to go is effective dynamic range (reduced overall contrast especially in the shadows), followed by ghosts of the entrance pupil.
Especially when it is known in advance that the lens is going to be stopped down, one can only benefit from a deep lenshood that might slightly vignet when the lens is used wide open. For this purpose, an adjustable lenshood, like the one from
Lee filters, will add flexibility (although it might slow down the setting up for a shoot). Sometimes one can use a ready made lenshood intended for a different (longer focal length) lens, if the diameter is the same.
What about going from the 70-200 L IS 2.8 v. I and the new version II?
Again from reading the MTF curves, I'd expect the version II to be significantly more contrasty (mainly at the longer FL end), and having talked with Nicolas about the difference between the two, he confirms it (he traded up to the version II, so he can tell from experience). Also his keeper rate due to better AF went up drastically. However, to accomodate a 70mm focal length (wide open at f/2.8) makes me suspect that the lenshood may be seriously under-dimensioned for the 200mm setting. Lenshoods with zooms are usually a serious compromise for the longer focal lengths (unless the front lens element sinks deeper with longer focal lengths).
These are very important concepts for me. Of course the answer has to include say an ISO of 320 v. and ISO of 800 or 1600.
I understand only too well, the challenges rarely come alone. Well, boosting the ISO in Canon cameras will reduce the sensor DR. But that may be a somewhat moot point if the lens doesn't deliver enough contrast. However, the effects do add up (they actually multiply). That's why boosting 'exposure' in a Raw converter rather than with a higher ISO may also be beneficial.
Lastly, is a Tiffen polarizing filter likely to have the same effect as an inferior lens in reducing DR or should one therefore get the most elite filters for that reason?
I never use a filter, unless it adds more than it destroys. Polarizers are the exception to a general rule, since they can achieve things that cannot be mimicked in postprocessing. However, they will also help destroy contrast by adding multiple air/glass surfaces. The light lost at each surface (some 2% per surface if uncoated) will end up somewhere where it isn't helping the image. Only high quality coatings can
reduce the negative effects of glare cause by filters, but
not eliminate the negative effects entirely. In fact they may introduce other effects like color casts across the field of view. So filters are a compromise, and they warrant even deeper lenshoods because the front surface is more at the front.
More than your likely range of immediate knowledge perhaps but still I'd like the gestalt of your feelings on this. Would I be able to teat this simply with Imatest™ which I have but have not setup. (Ashamed!!!)
Testing is not a simple thing, even though Imatest makes it easier by removing some of the repetitive/boring and thus error prone tasks when evaluating tests. The tests themselves need to be well controlled in the first place. Not all that easy.
Imatest does have a
specific procedure which allows to quantify the veiling glare characteristics of a lens, by adding a light trap at the end of a stepwedge, mounted in a bright field.
Cheers,
Bart