Rodenstock Rodagon 80mm f4 - No f16??

[teekoh]

Hi I bought a Rodagon 80mm f4 of Ebay. When I adjust the aperture the lowest I can select is f11 even though there is a marking for f16. Did I get a faulty lens?

Thanks,

 

[Aron]

Newer design Rodenstock enlarging lenses allow for a working aperture to be preselected, so that you don't have to count click stops in the dark as you stop down from wide open (focusing) to working aperture (exposing). You'll probably see a tiny notch under the f/stop value 11 when you set it on your lens. Now pull the aperture ring down and turn it to your preferred working aperture. By turning it to f/16 then letting it go back you can freely select any aperture between f/4 and f/16.

Unless you need unusually generous depth-of-field, there is no need for that lens to be stopped down further than f/8 or so.

 

[bdial]

To expand a little on Aron's comment, the lens is at its sharpest 2 or 3 stops from the maximum aperture. So generally speaking, there is little reason to stop down further. If you can't select f/16, think of it as a blessing in disguise

 

[ic-racer]

Many condenser heads will be too bright at f8 or f11 when making small prints. Perhaps hundreds of threads like this "...printing time too short..." "...I was told not to stop down past f8..."

If the lens is from e-bay it is probably busted. My guess is that it was taken apart and re-assembled wrong. Does the lens have any stigmata of being disassembled?

 

[Bill Burk]

Of course what Aron is saying in the first paragraph... The "Pre-Set" mechanism might be set at f/11 right now... and you might only need to clear the preset so that you can select f/16.

 

[teekoh]

Amazing thank you everyone for sharing your knowledge! All I had to do was pull down on the aperture ring and rotate it all the way to the opposite direction to reset the preset. There is actually a f22!

 

[teekoh]

Newer design Rodenstock enlarging lenses allow for a working aperture to be preselected, so that you don't have to count click stops in the dark as you stop down from wide open (focusing) to working aperture (exposing). You'll probably see a tiny notch under the f/stop value 11 when you set it on your lens. Now pull the aperture ring down and turn it to your preferred working aperture. By turning it to f/16 then letting it go back you can freely select any aperture between f/4 and f/16.

Unless you need unusually generous depth-of-field, there is no need for that lens to be stopped down further than f/8 or so.

Is the print quality at f16 and f22 significantly decreased? I am struggling with short development times even with a diffuser enlarger and using #4 Ilford filter I'm still getting 4 or 5 second exposures.

 

[ic-racer]

Is the print quality at f16 and f22 significantly decreased? I am struggling with short development times even with a diffuser enlarger and using #4 Ilford filter I'm still getting 4 or 5 second exposures.

I'm glad I was wrong about the lens being damaged. Nice to see you have it figured out.

With a 'small' print the theoretical maximum resolution of both f16 and f22 can both be greater than the resolution of the paper; so there can be no difference in print quality. In my opinion, it is much simpler to just test it out with whatever one considers 'small' rather than to account for all the mathematical variables and try to calculate it.

 

[ath]

Is the print quality at f16 and f22 significantly decreased?

Depends on the enlargement. If you have short times because of small print size just stop down. You will not see a difference in a small print.