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Canon EF> FX Adapter with aperture iris


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I’ve mentioned this adapters with aperture in my other thread concerning the Petzval 85mm lens. I think it is worth making a special mention of these peculiar adapters.

 

 

http://www.fuji-x-forum.com/topic/747-petzval-85mm-f22-in-fujifilm-mount-anyone/page-3

 

$_57.JPG

 

 

The adapter is a “ dumb” adapter in as much as it has no electrical connections between camera and lens.

 

Of course in the case of adapting a Canon EF lens to any camera the best approach would be to have an electrical actuator of some sort, but making one is very expensive and complicated, so, in China, someone thought of bypassing the problem this supposed mechanical way.

 

Canon EF lenses have an aperture which is normally activated electrical between camera and lens so you simply can’t do it mechanically but they placed an Iris aperture in de adapter .

 

This solution is not one that follows any optical principles and in fact it is not a “ solution” at all!

 

The aperture , normally, has to be, for a number of reasons, placed somewhere in the “ middle” ( take this word with a grain of salt since was used for simplicity) of the lens. 

 

Apertures in that position serve the purpose to, yes, reduce the amount of light and increase the apparent depth of field, but also help correcting aberrations and generally improve the lens performance.

 

So, Is there really a function that an aperture iris put between the camera and the lens can perform? Not really!

 

If you are looking to do the same thing with these adapters that you can do by turning on a normal lens the aperture, no, you will be bitterly disappointed.

 

 

These adapters are very quickly inducing vignetting in your lens though you are using a full frame lens on a APS-C sensor (so some of it will fall outside the image circle).

 

But if you are looking at the occasional use of an EF lens that you are using completely open anyway, or a lens like the Petzval (which does have its aperture but where you can add this second aperture) this can be leading to some interesting (see my other thread) results.

 

http://www.fuji-x-forum.com/topic/747-petzval-85mm-f22-in-fujifilm-mount-anyone/page-3

 

there are several tests of these adapters (several brands all sorts of prices, my advise is not to spend a great deal of money on these they are pretty much the same, just choose one which seems to be made robustly), some involve other cameras.

 

This one @https://www.youtube.com/watch?v=3eIkOwvaQZI for example is about a Sony Nex-7 and a Fotodiox adapter.

 

 

maxresdefault.jpg

 

The author claims there is an increase in depth of field... actually I should think that more than any increase of depth of field, the iris aperture in this position really only adds some contrast to the lens ( and therefore the numbers of the tape measure appear to be “ sharper” ).

 

Happy experimenting!

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  • 1 year later...

 

 

21 hours ago, robbie p said:

I purchased one of these adapters, don't waste your money they just give you vignette totally useless  

well, have you read what I wrote?

 

I think that you didn’t, so let me extract that things pertaining to your point.

 

“...The aperture , normally, has to be, for a number of reasons, placed somewhere in the “ middle” ( take this word with a grain of salt since was used for simplicity) of the lens. 

 

Apertures in that position serve the purpose to, yes, reduce the amount of light and increase the apparent depth of field, but also help correcting aberrations and generally improve the lens performance.

 

So, Is there really a function that an aperture iris put between the camera and the lens can perform? Not really!

 

If you are looking to do the same thing with these adapters that you can do by turning on a normal lens the aperture, no, you will be bitterly disappointed.

 

 

These adapters are very quickly inducing vignetting in your lens though you are using a full frame lens on a APS-C sensor (so some of it will fall outside the image circle).

 

But if you are looking at the occasional use of an EF lens that you are using completely open anyway, or a lens like the Petzval (which does have its aperture but where you can add this second aperture) this can be leading to some interesting (see my other thread) results.

 

http://www.fuji-x-forum.com/topic/747-petzval-85mm-f22-in-fujifilm-mount-anyone/page-3..."

Edited by milandro
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