35mm adaptors affecting Dynamic Range and resolution.

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High1ander

Well-known member
I did some searches but couldn't find any information IF 35mm adaptors have any impact on the Dynamic Range. What is the difference in resolution, this one I am sure there is some difference I would even imagine there is a difference between all adaptors.

Is there are chart available where 1 or 2 lenses have been tried on several 35mm adaptors to check these things? If so, I would love to read it :)
 
35mm adapter does not affect dynamic range, nothing short of a camera sensor hack (like Andromeda) can do that. What an adapter does is softens up the transition between the highlight area so that your whites blown out more gradually which is more pleasing to the eye.
 
Huy Vu said:
35mm adapter does not affect dynamic range, nothing short of a camera sensor hack (like Andromeda) can do that. What an adapter does is softens up the transition between the highlight area so that your whites blown out more gradually which is more pleasing to the eye.
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That's what I figured, except the highlights, but it makes sense now when I think about it.

Thank you for the answer!

Still, is there a general "you lose about 10% in lines of resolution" rule for adaptors?
 
I believe DOF adaptor do in fact effect an images gamma and dynamic range. In fact any filter that diffuses tends to bring your black levels up and flatten the image slightly. I guess, I should look at a waveform before and after. Something tells me a DOF adaptor will have a flatter line.
 
I am surprised that there is no available chart or comparison done. I would think that companies would love to say "we got the best Dynamic Range on our 35mm and you lose less resolution".

Is there a reason to consider buy 35mm X over Y because of better resolution/DR or is it all just matter of taste (nicer highlights) because the difference in quality between 35mm is non-existing (regarding DR and resolution)?
 
High1ander said:
I am surprised that there is no available chart or comparison done. I would think that companies would love to say "we got the best Dynamic Range on our 35mm and you lose less resolution".
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That's because it's not a meaningful comparison unless there's a lens on the adapter. A $10,000 cinema lens is going to be sharper than a $50 SLR. Not to mention everybody uses different camera with different optics that's going yield different degree of sharpness. It's something that's very difficult to measure objectively.
 
I have noticed that when I have my adapter on and I am using a 50mm with fairly open aperature, if I am doing a close up of a person focused on them, with the zebras on just not seeing zebras on say for example hot overcast sky if I rack focus to the sky the zebras appear, indicating to me that the blur of the out of focus skies diffuses their intensity but when focused on and sharp their intensity increases. Not very scientific I know, but this is what happens on my sgpro.
 
Because the effect of the adapter's screen on gamma is somewhat analogous to a diffusion filter, it will vary greatly depending upon how hot the highlights are. Hotter highlights>more potential flaring or dispersion into the shadow areas. Thus it would impossible to come up with a simplistic gamma adjustment figure. It depends on the shot.

Lenny levy
 
This is an area often theorized upon, and never properly investigated. We've invested in the DSC labs 72db (13 step) OSG with a white to black ratio of 4000:1. Used on the Ambi2 rear illuminated system with a waveform monitor, we can't figure out a better way to explore the range question objectively :-) What remains though is a methodology for testing the unit when it is not square to the chart. We need to figure this out to test shallow DOF situations too.
 
I'm going to alter what I said before. Although it will vary on the shot , it would be interesting to run tests under relatively normal exposures.

Be my guest Dennis.
Lenny Levy
 
Huy Vu said:
That's because it's not a meaningful comparison unless there's a lens on the adapter. A $10,000 cinema lens is going to be sharper than a $50 SLR. Not to mention everybody uses different camera with different optics that's going yield different degree of sharpness. It's something that's very difficult to measure objectively.
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I know, but you would still be able to do some comparison if you use 1-3 lenses on the various 35mm adaptors on one camera (or more) and do some resolution tests. Obviously things will behave differently with highlight flares, etc. and that is hard to test, and that is a matter of taste. But checking which adaptar that has the best resolution shouldn't be a matter of taste.

Take an HVX 200 (or better HPX 500) use canon 100$ lens and a 1000$ lens, compare between 3-5 different 35mm adaptors and that should be a pretty good benchmark for determining DR and resolution.
 
Texanite said:
I agree, I think the ground glass works in a similar fashion to how a lo-con filter effects those things.
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I know I just posted this yesterday, but I've never really thought about the technical workings of lo-con filters beyond the fact that some seem to add a little diffusion. But I've not worked with them much at all. Interestingly enough a quick Google turned up the following which seems to be relevant:

tiffen.com said:
LOW CONTRAST filers work by spreading light from the highlights to the darker areas. Shadows are lighter, enabling you to see more detail.
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I think that same kind of effect is present because of the ground glass imaging elements of these 35mm adapters.
 
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