Using Sigma lens on a Sony A7

bazzerkap

Novice Member
I have a Sony A7Riii camera and happened to drop on a Sigma 105mm prime at local auctions. It wa sonly £15. But it was Canon fit. However I have an adaptor from Canon to Sony Fe.

I tried to use the lens in manual mode but no way could I close down the aperture. Even whnenusing the manual aperture setting while it looked in the viewfinder as if it was closing, when I took a photo it just took it at wide open (F2.8).

I am now using it in using Aperture priority mode and shutter/ISO etc is adjusted automatically. The results are very good and it's a pity the lower aperture settings cannot be used. Does anyone know if it can be done? There are no aperture rings on the lens so assume it is all done electronically by a Canon camera.

I attach a couple taken at F2.8 on Ap priority.

Cheers.
 

Attachments

  • odrodechurch sigma 105 test2.jpg
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  • sigma 105mm F2_8 test1.jpg
    sigma 105mm F2_8 test1.jpg
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two2midnight

Distinguished Member
I have a Sony A7Riii camera and happened to drop on a Sigma 105mm prime at local auctions. It wa sonly £15. But it was Canon fit. However I have an adaptor from Canon to Sony Fe.

I tried to use the lens in manual mode but no way could I close down the aperture. Even whnenusing the manual aperture setting while it looked in the viewfinder as if it was closing, when I took a photo it just took it at wide open (F2.8).

I am now using it in using Aperture priority mode and shutter/ISO etc is adjusted automatically. The results are very good and it's a pity the lower aperture settings cannot be used. Does anyone know if it can be done? There are no aperture rings on the lens so assume it is all done electronically by a Canon camera.

I attach a couple taken at F2.8 on Ap priority.

Cheers.
It sounds like the Canon to Sony adaptor may be the problem. What one are you using?
 

Ugg10

Distinguished Member
If it is an older Sigma lens then it may be the chip in the lens. Quite a while back some of the older Sigma lenses needed re-chipping to work with the early digital cannon cameras the typical error was that the aperture did not work and was fully open all the time so it may be this is what you are experiencing. I think the window to have the lenses re-chipped is well and truly over (I have two sigma that don't work with my newer digital cameras and these could not be re-chipped when I inquired about 7 or 8 years ago). If you have a depth of field preview button I think there was a hack something along the lines of holding this down when taking the shot but not 100% on they, maybe a google will throw up something.
 

bazzerkap

Novice Member
It's the same with any 'older' lens I use on the Sony A7Riii I have tried Pentax, Ziess and others with different mounts too and always the aperture stays wide open. I will investigate the preview idea thanks.
 

MaryWhitehouse

Well-known Member
Does sound like the adapter is the problem. From memory (so most likely faulty) of similar efforts last year you need a decent adapter to pass any electronic signal to the lens and many just don’t, especially with Canon lens. Exactly which adapter do you have?
 

bazzerkap

Novice Member
I'm using Pixco SA-NEX, K&F Nikon to NEX, K&F M42 to NEX and fotodiox Canon to NEX adaptors. I realise these are only the basic cheap adaptors but I am only trying out old lens picked up at auctions to see if they are any good. So does not justify buying an expensive adaptor for my needs. I just hoped there would be a simply way to control the aperture. Seems like I would need a more expensive adaptor to do this which I am not willing to bouy. I can mange for some shots with wide-open apertures. Ideal for say portraits and close-ups etc.
 

MaryWhitehouse

Well-known Member
Ah yes that’s the problem with Canon for you, no mechanical aperture control. As I’m sure you’ve seen get older Nikon AF lenses with an aperture ring and they work well manually.
 

two2midnight

Distinguished Member
I'm using Pixco SA-NEX, K&F Nikon to NEX, K&F M42 to NEX and fotodiox Canon to NEX adaptors. I realise these are only the basic cheap adaptors but I am only trying out old lens picked up at auctions to see if they are any good. So does not justify buying an expensive adaptor for my needs. I just hoped there would be a simply way to control the aperture. Seems like I would need a more expensive adaptor to do this which I am not willing to bouy. I can mange for some shots with wide-open apertures. Ideal for say portraits and close-ups etc.
Have you got 'release without lens' enabled in your settings?
https://www.sony.co.uk/electronics/support/articles/00019297

I've got a cheap Commlite adaptor (£60) which works OK with Canon and Sigma lenses on my A6000 and A7. I have this setting enabled (I'm guessing I did this for a reason but can't remember why).
Worth giving the setting a try as you say it looks as if the lenses are stopping down in preview.
 
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