Home · Register · Join Upload & Sell

Moderated by: Fred Miranda
Username  

  New fredmiranda.com Mobile Site
  New Feature: SMS Notification alert
  New Feature: Buy & Sell Watchlist
  

FM Forums | Sony Forum | Join Upload & Sell

  

Archive 2017 · Focusing IR converted A7R

  
 
Herbc
Offline
• •
Upload & Sell: Off
p.1 #1 · p.1 #1 · Focusing IR converted A7R


I have some trouble with infinity focus on some Loxia lenses with this camera. Can someone recommend a device, i.e. a focusing ring or such, that will allow me to solve this problem?


Oct 16, 2017 at 10:00 AM
retrofocus
Offline
• • • • • •
Upload & Sell: Off
p.1 #2 · p.1 #2 · Focusing IR converted A7R


Interesting observation - I was always curious how newer E-mount lenses work on IR-modified A7 series cameras. It might actually be a lens issue - since all these newer lenses have no longer an IR metering scale, we can't tell if they are even made to be used for IR light photography.


Oct 16, 2017 at 10:19 AM
realVivek
Offline
• • • •
Upload & Sell: Off
p.1 #3 · p.1 #3 · Focusing IR converted A7R


Assuming the conversion was done in a way that it allows infinity focus, i would suggest that use use live view, focus wide open to infinity and then stop down as required.

Generally, IR focus is closer than the visible infinity. So, do not set the focus to infinity as shown on the lens!

It is likely to be at ~10m (varies from lens to lens).

Herbc wrote:
I have some trouble with infinity focus on some Loxia lenses with this camera. Can someone recommend a device, i.e. a focusing ring or such, that will allow me to solve this problem?





Oct 16, 2017 at 10:36 AM
DannyBurkPhoto
Offline
• • •
Upload & Sell: Off
p.1 #4 · p.1 #4 · Focusing IR converted A7R


Do you mean that you have difficulty seeing if it's properly focused (in the EVF) for infinity, or that your lenses won't reach infinity?

I also have an A7R (converted by Kolari to 850nm) and I use Loxia lenses, among others, with no problem. I always focus with fully magnified EVF view; are you doing the same?



Oct 16, 2017 at 11:54 AM
Jimi3
Offline
• • •
Upload & Sell: Off
p.1 #5 · p.1 #5 · Focusing IR converted A7R


I had a 5d mark ii that was converted to IR, and I simply couldnt reach infinity focus with that camera and my old sigma 12-24. Seems strange given that I've always been told that infrared light focuses closer than visible, but it just wouldn't quite get there. I eventually had to get a 12-24ii that WOULD focus on infinity. Hope this isn't a similar case with your lenses.


Oct 16, 2017 at 02:23 PM
Herbc
Offline
• •
Upload & Sell: Off
p.1 #6 · p.1 #6 · Focusing IR converted A7R


I am using a Loxia 21mm, and have some question about how well the IR is focused at infinity.

When I use a Leica M mount lens, I have an adapter that lets me go where I need to with those lenses to get a good IR focus.

I will have another go at it with a 35mm loxia and see what I find.
thanks for the replies. results soon.



Oct 16, 2017 at 02:51 PM
retrofocus
Offline
• • • • • •
Upload & Sell: Off
p.1 #7 · p.1 #7 · Focusing IR converted A7R


Jimi3 wrote:
I had a 5d mark ii that was converted to IR, and I simply couldnt reach infinity focus with that camera and my old sigma 12-24. Seems strange given that I've always been told that infrared light focuses closer than visible, but it just wouldn't quite get there. I eventually had to get a 12-24ii that WOULD focus on infinity. Hope this isn't a similar case with your lenses.


I am using the same IR-converted 5D MkII camera, but I never ran into this problem. And yes, focusing in IR light should always be closer then visible, so you wouldn't need to go to the lens' infinity mark or certainly not above it. Did you try to focus manually by using LiveView, or did you rely on AF? An IR-converted AF system is normally re-calibrated with a 50 mm lens by the company which did the conversion. There can be AF offsets in the wider or longer focal lengths.



Oct 17, 2017 at 09:52 AM
Herbc
Offline
• •
Upload & Sell: Off
p.1 #8 · p.1 #8 · Focusing IR converted A7R


All manual focus. I have never had a lot of luck with AF in IR even if the lens was calibrated, which I usually send along with the camera. The A7R is my 3rd IR camera. I looked at some shots I took this pm and they are ok on a laptop. I will print some tomorrow to be sure.

Thanks to all.



Oct 17, 2017 at 06:56 PM





FM Forums | Sony Forum | Join Upload & Sell

    
 

You are not logged in. Login or Register

Username       Or Reset password



This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.