Chamonix camera 45N-1 focusing error

[Jeremy Moore]

Bob, so I should be able to find a fresnel/GG combo that works really well without the focus shifts nor any funky corner issues for lenses that range from 38mm to 450mm? Which ones should I look for? BTW, I won't be focusing through the fresnel... just getting my compositional bearings.

Mike, for my own edification, do you regularly shoot with 38mm - 450mm lenses on one camera?

[Mike1234]

Mike, for my own edification, do you regularly shoot with 38mm - 450mm lenses on one camera?

Jeremy,

I plan to, yes. When I shot 4x5 years ago I used 65, 90, 150, 210, and 300mm lenses and there were times I wished I had a wider or longer lens. BTW, I'll only be shooting 6x12cm with the 4x5in camera and the lenses are 38, 58, 90, 135, 200, 300. I don't know whether I'll ever shoot with a 450 on 6x12cm but I have it for the 5x12in kit anyway so I may as well take it along for the ride. I'm sure the 58 through 200 will see the most use.

[Mike1234]

Mike,

It seems like one Fresnel will be enough for you if you are not going to focus through it. If you compose with the Fresnel and then focus finely using the GG, you have nothing to worry about.

David,

You're saying I won't have to worry about those funky corner issuse with a mismatched fresnel where the corners are masked with rings? Those really bug me because I can't see the image to compose.

[Peter K]

Bob, so I should be able to find a fresnel/GG combo that works really well without the focus shifts nor any funky corner issues for lenses that range from 38mm to 450mm? Which ones should I look for? BTW, I won't be focusing through the fresnel... just getting my compositional bearings.

Short focal fresnel-lenses behind the gg will work also with longer taking lenses - I don't know up to 450mm-lenses - but long focal fresnel-lenses won't work well with short taking lenses.

[Mike1234]

Short focal fresnel-lenses behind the gg will work also with longer taking lenses - I don't know up to 450mm-lenses - but long focal fresnel-lenses won't work well with short taking lenses.

So the key is to find a fresnel matched to the 38mm used behind the focus panel... and all is well all the way through 300mm? BTW, I not convinced a fresnel is really needed for 200mm and longer for 6x12cm or 4x5in anyway.

[Jeremy Moore]

Jeremy,

I plan to, yes. When I shot 4x5 years ago I used 65, 90, 150, 210, and 300mm lenses and there were times I wished I had a wider or longer lens. BTW, I'll only be shooting 6x12cm with the 4x5in camera and the lenses are 38, 58, 90, 135, 200, 300. I don't know whether I'll ever shoot with a 450 on 6x12cm but I have it for the 5x12in kit anyway so I may as well take it along for the ride. I'm sure the 58 through 200 will see the most use.

Makes sense. I only shoot with 2-3 and 90% of my work is with 1 so I was just curious.

[Bob Salomon]

Bob, so I should be able to find a fresnel/GG combo that works really well without the focus shifts nor any funky corner issues for lenses that range from 38mm to 450mm? Which ones should I look for? BTW, I won't be focusing through the fresnel... just getting my compositional bearings.

We have had no complaints with 35mm up with the Linhof Fresnel. I have no idea if it will fit your camera. You should also have no problem with a Sinar Fresnel. We have also not had any reported problems with a Wista Fresnel.

Bear in mind that cameras function differently. Linhof cameras have either an optical axis front tilt or an asymmetrical axis front tilt. Many folding cameras have a base tilt on the front. With an optical axis tilt there is no, or very little shift of the image placement on the gg. With a base tilt camera there can be a great amount of image displacement - depending on the amount of movement. When you use a loupe and an enhancing means it will be necessary for your eye to remain in the optical path to maintain optimal screen brightness. This can become tricky especially with very wide lenses. It usually means that the loupe ends up tilted and displaced, especially with a base tilt camera. That is one reason why on Linhof's asymmetrical axis M679 system cameras the Fresnel is cut off center and has a handle on it so it can slide to keep the optical center of the Fresnel in the optical center of the lens as tilts are made. If this was not done you could black the entire image out. Guess 121 years of camera manufacturing experience can solve vexing problems.

[Mike1234]

Bob, okay I'll study a bit more and look into the brands you mentioned.

[Peter K]

BTW, I not convinced a fresnel is really needed for 200mm and longer for 6x12cm or 4x5in anyway.

That's true if one uses no focusing-mirror or a focusing and measuring bellows.

[Mike1234]

That's true if one uses no focusing-mirror or a focusing and measuring bellows.

By "focusing mirror" you mean a reflex hood? Maybe not but I'm not ruling one out. There is a problem with these when used with a mismatched fresnel because it fixes the eye in one spot making one unable to move his head around to see the image, right? By "focusing and measuring bellows" you mean a monocular hood? I might want one of these but they have the same problems as the "focusing mirror"?