Copal sizes

[decoff]

Im just getting into LF and wanted to know how the copal size relates to the lenses. For instance in looking to purchase a 300mm lens, I see some in a Copal 1 and some in Copal 3. I know the size of Copals, but what I do not know if why these would be differant from the same FL lens, and/or which is appropriate for that or other particular lenses

[Bernice Loui]

Depends on the lens and what image goal needs are.

Best to decided on print image goals first, then what film-process, then lens needed to meet these needs with the camera nothing more than a support device for these needs.


Bernice

[Len Middleton]

Im just getting into LF and wanted to know how the copal size relates to the lenses. For instance in looking to purchase a 300mm lens, I see some in a Copal 1 and some in Copal 3. I know the size of Copals, but what I do not know if why these would be differant from the same FL lens, and/or which is appropriate for that or other particular lenses

decoff,

The shutter size is related to the diameter of the lens where it mounts to the shutter, and that will in turn depend upon the lens construction and the size of the glass it needs to accommodate.

What I expect you are seeing is a 300mm f5.6 lens mounted in a Copal 3 versus a 300mm f9 lens in a Copal 1...

If you look at images and / or specs for those two different lenses, you will find the former being extremely large relative to the latter.

Hope that helps,

Len

BTW, Bernice is right...

[Alan Gales]

Just to add to Bernice and Len...

Besides largest maximum aperture, the amount of coverage the lens produces affects it's design too. A 300mm lens that produces a large enough image circle to cover 8x10 is going to be larger than a 300mm lens that only covers 4x5.

[gary mulder]

A 300mm f5,6 has a max aperture diameter 300/5,6=53,57mm. A 300mm f9 has a max aperture diameter 300/9=33,33mm. That's why you need larger shutter for the first lens.

[Drew Wiley]

You need to be more specific about exactly which 300's you're comparing. Just because something has a smaller shutter does not necessarily mean it has less coverage.

[Alan Gales]

You need to be more specific about exactly which 300's you're comparing. Just because something has a smaller shutter does not necessarily mean it has less coverage.

You make a good point, Drew. There are lenses that are in smaller shutters that do have quite a bit of coverage. I guess like Bernice said, it all depends upon what the designer's image goal needs were.

[decoff]

Thanks for the feedback and comments. Maybe I needed to be a bit more specific. In regards to comparing the same focal length lenses, Im educated enough to not compare lenses of differant shutter sizes, so Im just comparing Rodenstock vs Nikon vs Schnieder in this case for a 300 5.6. My understanding on design would apply to only just that. If Im doing Landscape I could get away from an F9 lens for less money where if I wanted to do Portrait, a 5.6 might be more appropriate. With that said, the 300mm Im looking to acquire would be able to do both, so design dosnt necessarily drive the decision. My question more in reference to seeing some with Copal 1 and some with Copal 3 of the SAME speed and FL. I've been a 35mm and MF shooter for a long time, so finding the FL i prefer for various subjects in LF might take a little practice. In addition to getting used to bellows and reciprocity calucations. In addition, not knowing which brand at certain FL's are better builds. Rodenstock over Nikon, etc..

[decoff]

You need to be more specific about exactly which 300's you're comparing. Just because something has a smaller shutter does not necessarily mean it has less coverage.

Rodenstock APO-Sironar N 5.6 vs Nikkor W 5.6

[Oren Grad]

Rodenstock APO-Sironar N 5.6 vs Nikkor W 5.6

Those both come mounted in #3 shutters. If a listing seems to indicate otherwise, it is an error.