Chamonix 45N-1 Testing Procedure

Based on this thread I'm going to be doing an actual test with film and a Chamonix 45N-1 camera this evening.

I will make 4 photographs. 2 with a 90mm lens and 2 with a 135mm lens.

The camera will be firmly mounted to a Majestic Tripod with 6" bed indoors and focused on a fixed subject 10-15 feet away.

I will make 1 photograph to the best of my ability with a 90mm f/5.6 Super Angulon at f/5.6. I will then remove the fresnel, refocus my camera if need be due to the fresnel being removed, and make another photograph at f/5.6.

I will then repeat this process using a 135mm f/5.6 Symmar-S.

I will light these photographs with flash and use a shutter speed of at least 1/125th of a second to avoid motion blur. I will shoot Ilford FP4+ and develop it in Pyrocat HD using a 2-bath development in a Jobo 3010 with 6 other sheets I need to develop. I will scan the resultant images and post them back to this thread.

Anyone that may have an issue with how this test is conducted and nitpick it later are given the opportunity--RIGHT NOW--to make suggestions on the testing procedure.

Is there a way, without going overboard, to place a secondary subject somewhat closer to the camera in the same shot? It might be nice to see, if the fresnel fails, to see not only the main subject getting blurry but to also see the secondary subject getting sharper.

That would also serve as a check on camera shake issues, etc--if the secondary subject is sharper than it can't be camera shake.

--Darin

I do not mean to nitpick.
But if you want to be rigorous you have to introduce statistics in this.

Simple: everytime just make 4 sheets instead of one. And make sure you completely and randomly defocus the camera before each sheet.
This way, you can avoid the nitpicking on your ability to focus and on the focusing error probability on a single sheet test procedure.

Also defocus randomly before refocusing without the fresnel. So you won't be influenced by the current position of the standards when you focus the second shot.

Just my 2cents.

Can’t wait to see the results though.
Good initiative.
Thanks for doing / sharing it.
regards,
CA

Quote:

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Originally Posted by Darin Boville

Is there a way, without going overboard, to place a secondary subject somewhat closer to the camera in the same shot? It might be nice to see, if the fresnel fails, to see not only the main subject getting blurry but to also see the secondary subject getting sharper.

That would also serve as a check on camera shake issues, etc--if the secondary subject is sharper than it can't be camera shake.

--Darin

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Good idea. I'll incorporate this.

Quote:

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Originally Posted by Darin Boville

Is there a way, without going overboard, to place a secondary subject somewhat closer to the camera in the same shot? It might be nice to see, if the fresnel fails, to see not only the main subject getting blurry but to also see the secondary subject getting sharper.

That would also serve as a check on camera shake issues, etc--if the secondary subject is sharper than it can't be camera shake.

--Darin

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Yes, some kind of long ruler in the shot. so we can appreciate where exactly the focus is.
easier to say it than to do it though.

Yes Clement. My thought exactly. Run a tape off the lens axis from in front of the subject to behind it. It should show nicely where the focus actually is.

Okay, as my ability to focus a camera has been called into question I will go one better than doing a test with my camera at home.

I will do this test with my Chamonix mounted to a Cambo studio stand with a Betterlight Super8K camera back at work using a ZigAlign system to make sure everything is parallel. This will also remove any question about the development/scanning of the film and also remove any inconsistencies due to different film holder depths.

I can also run a ruler at an angle to the plane of focus to see how/where the focus is shifting.

Jeremy, do you have a wider lens to test with or can you borrow one or more? Adding a 65 and even a 47 would be great... would add to the validity of the results. Sorry to complicate things.

Quote:

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Originally Posted by Mike1234

Jeremy, do you have a wider lens to test with or can you borrow one or more? Adding a 65 and even a 47 would be great... would add to the validity of the results.

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No, 90mm is the widest lens I own and if there is a focus shift happening with a 90mm then I see no reason to test wider.

I am planning on making the tests with the Betterlight tomorrow or Friday and *may* have a 2nd Chamonix 45N-1 from a different batch to use for this test too, but that is still unknown at the moment.