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How to : test your film bodies without film
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PostPosted: Wed May 20, 2020 7:41 pm    Post subject: How to : test your film bodies without film Reply with quote

I realized an inversion ring with a M42 body cap and a 49mm filter holder (comes out from a Cokin system). If I had an inversion ring for EOS I could do the same in the opposite order (reversed lens on digital camera instead of M42 body) :


With cameras :


SV in test on 5D :


For the test, I used a 150/4 lens to limit the vignetting.
- First try with M42 body closed, check that the photo is really black. Do not forget to mask the eyepiece.
- Then open the back of the body to be tested
- Then, body to be tested in Bulb mode, search with the digital body a zone and parameters that allow to use the speed to be tested
- Set the body to be tested at the wanted speed and the digital body to M mode 2" pose
- Fire the digital body, then the body to test (always with eyepiece closed, a shutter wire can be useful)
- Check that exposure is OK on whole photo, compare it to previous step if you took one photo

Examples with a black SV body on my 5D :

Lens without nothing (1/125) :


Lens with inversion ring, we can see a small swirl bokeh effect (1/125) :


Light leak check, duration 2" :


SV on Bulb, 5D at 1/60 :


SV at 1/60, 5D at 2" :


PostPosted: Thu May 21, 2020 1:16 pm    Post subject: Reply with quote

Im not sure what this is achieving. The translation from the French is a little confusing too. Perhaps that's me. However, if it is what I think it is it seems like a good idea.

Are you checking shutter speeds on the film camera?


PostPosted: Thu May 21, 2020 3:19 pm    Post subject: Re: How to : test your film bodies without film Reply with quote

CarbonR wrote:
...
Lens without nothing (1/125) :


Lens with inversion ring, we can see a small swirl bokeh effect (1/125) :




I understand the test but not the purpose of these.

Also I chuckled at the camera with Canon under black tape but bright red Canon strap.Smile


PostPosted: Fri May 22, 2020 2:34 pm    Post subject: Re: How to : test your film bodies without film Reply with quote

visualopsins wrote:
I understand the test but not the purpose.


Exactly. Why not simply run a B&W film? If you develop it yourself, the cost of 12-18 frame strip is $3 or so.


PostPosted: Fri May 22, 2020 3:45 pm    Post subject: Re: How to : test your film bodies without film Reply with quote

Gardener wrote:
visualopsins wrote:
I understand the test but not the purpose.


Exactly. Why not simply run a B&W film? If you develop it yourself, the cost of 12-18 frame strip is $3 or so.


Actually I wrote "purpose of these" referring to the two images quoted. The purpose of the test is quite clear.

Using the digital camera is virtually free, a consideration perhaps for somebody with multiple cameras to test, and those retesting after asjustments.


PostPosted: Fri May 22, 2020 3:53 pm    Post subject: Re: How to : test your film bodies without film Reply with quote

visualopsins wrote:
...for somebody with multiple cameras to test, and those retesting after asjustments...

... owning a proper (optical) shutter tester is a must.


PostPosted: Sat May 23, 2020 9:33 am    Post subject: Reply with quote

I dont understand the purpose of this. Are you checking light leaks, shutter speeds?


PostPosted: Sat May 23, 2020 2:16 pm    Post subject: Re: How to : test your film bodies without film Reply with quote

Gardener wrote:
visualopsins wrote:
...for somebody with multiple cameras to test, and those retesting after asjustments...

... owning a proper (optical) shutter tester is a must.


Must?!, yet here is a technique that works as well.

Yeah, get one that counts laser pulses.


PostPosted: Sun May 24, 2020 6:44 pm    Post subject: Reply with quote

philslizzy wrote:
Im not sure what this is achieving. The translation from the French is a little confusing too. Perhaps that's me. However, if it is what I think it is it seems like a good idea.

Are you checking shutter speeds on the film camera?


Yes, both speeds and light leaks.
Light leaks are tested with the rear of the camera closed.
Speeds are tested with the digital camera on M mode 2 sec exposure (this is enough to have time to use the film camera to be tested), so this is the sutter of the camera to be tested that makes the exposure.

visualopsins wrote:

I understand the test but not the purpose of these.

Also I chuckled at the camera with Canon under black tape but bright red Canon strap.Smile


Just to see what my inversion ring makes on the image that would be taken without it. This is not a part that has to be repeated each time Wink

In fact I started to blacktape the K100D and did it with the 5D too. Both have their red Pentax/Canon large strap, but the black tape make them look more like film bodies. I'va had several people surprised to see it is a digital body.

Gardener wrote:
visualopsins wrote:
I understand the test but not the purpose.


Exactly. Why not simply run a B&W film? If you develop it yourself, the cost of 12-18 frame strip is $3 or so.


I do not have films at $3, neither a free developper.
My 5D gives me an answer in less than 15 minutes, for free, while a film cost me money and cannot give its answer in less than approximatively 1h30. This does not make sens to spend 1/6th of the value of the camera I want to sell in just testing it without knowing if it will work. The only thing I cannot test with this technique is all that is related to film carrying. A compromise would be to first test it with the free technique, and if everything is OK, then I spend a film to check it with film, knowing that at least speeds are correct and it shows no light leak.