90mm lens.. 5.6 or 4.5?

[brian steinberger]

I currently have a Calumet 90 f/8 lens for my 4x5. I know that it's dark and hard to see with, but yesterday was an overcast day and I was trying to photograph with it, and I literally could not see to focus. I'm 23 years old, so I know it's not my eye sight. I would like to upgrade to either a 90 f/5.6, or 90 f/4.5. I don't backpack much, so weight is not an issue. I understand that the 4.5 will cost more also. My question is, as for viewing on the groundglass, how much difference will I see going from my f/8 now to a f/5.6? And would I gain even more by going with the f/4.5?

[Wilbur Wong]

What camera are you using, and are you using your original ground glass? The type of ground glass on a camera might have a greater effect than a 1 or 1 1/2 stop lens difference.

[Louie Powell]

Brian -

I have the same lens, and also found that it was difficult (impossible) to focus without a darkcloth. Using a darkcloth makes a big difference, and it's easy to focus wide open, but becomes more difficult if I try to focus stopped down on plain ground glass. Fortunately, with that lenss, focusing wide open is fine.

My camera is a Zone VI, and some months ago, Calumet unloaded a number of fresnels via the auction site. I was able to pick up one, and it's amazing how much difference that makes. With the fresnel in place, I can (with a darkcloth) focus with the lens stopped down if the light is fairly bright. Obviously, that's still a challenge under subdued light.

[GPS]

How much difference would you see? Exactly as much as between f/8 and a f/5.6. Would you gain even more by going to f/4.5? Go figure...

[Alan Davenport]

Darkcloth.

[Bruce M. Herman]

Brian,

I'm assuming that you are using a dark cloth.

The point of the some of the earlier answers is that going from f8 to f5.6 doubles the amount of light hitting the ground glass.

If you are using a conventional ground glass, adding a fresnel screen to your camerea will cost less and accomplish some of the same goals. Keep in mind that the Nikkor 90mm f8 lens is very popular among field photographers, so an f8 maximum aperture is not generally seen as a limitiation. Having said all of that, I personally find the f8 aperture a bit dark in low light situations even with a bright screen on my camera. I use a Fuji 90 mm f5.6.

A secondary expense that you may incur in moving to such a lens is related to filters. I use 100 mm Lee filters, which work fine with this lens But if you've been working with glass filters, you'll need to purchase new filters for your f5.6 or f4.5 lens. Just something to think about.

Best of luck,
Bruce

[Brian Ellis]

For the difference in price between an F8 and an F5.6 Super Angulon (don't know about other makes or about 90mm F4.5 lenses) you could just about get a Maxwell screen. I think that would do more for you than gaining a one stop difference in maximum aperture. When you're starting out not being able to see enough to focus on the ground glass another stop of light isn't going to be all that great. Plus the Maxwell would be of benefit with all your lenses. After years of using plain ground glass, Beattie bright screens, OEM Fresnels on several different cameras, and BosScreens I've settled on the Maxwell. IMHO it's the best of the bunch though the BosScreen is very good also and costs about $100 less than the Maxwell.

[Daniel Geiger]

I trust you already use a dark cloth, most likely the "horse blanket" type. Consider getting one that is a tube with a drawstring so that you can tighten it around the rear standard. I upgraded recently to one called black jacket (recently discussed in View Camera Magazine, maybe the issue before last), and it makes a truck load of difference.

I used a Schneider Superangulon 90f/8 and upgraded to a 90f/5.6 XL for my 4x5. The difference is mainly the coverage, brightness is less of an issue. I did notice that with a fresnel lens, when I inspect the corners of the image I have to look at the ground glass at and angle towards the center of the image. That gives a MUCH brighter image and allows for precise control of tilt/swing.

Hope that helps.