f1.2 or not f1.2?

[Ricardo Miranda]

It is the depth-of-field I am talking about, not how easy a fast lenses "snaps" into focus.

 

[craigclu]

It is the depth-of-field I am talking about, not how easy a fast lenses "snaps" into focus.

Yes, it must only seem to shallow the field when focusing. I had always assumed it was at least partially from a shallower depth of field along with the ability to more clearly focus and assure the focus by virtue of the brighter image.

 

[cooltouch]

I didn't know that. It always seems as if the fast optics snap in and out of focus more crisply... Just from the enhanced brightness, perhaps?

Not only that, but when a screen is optimized for a slower aperture, focusing accuracy suffers. For example, when I mount my FD 85mm f/1.2 to my AE-1 Program, I find it very difficult to focus accurately on a subject, whereas if I mount that 85mm on my F-1, I can focus with ease. It appears that the AE-1P can handle lenses as fast as f/1.4 without problems, but that additional 2/3 stop is just too much for it.

 

[Fixcinater]

Which focus screen do you have on the F1? If it's one of the finer grained, optimized for fast lenses screens, that doesn't surprise me!

 

[cooltouch]

My old F-1s both have the later Laser matte screens. I don't recall the letter designation, but they're plain matte screens in both cameras. The New F-1 has the Partial plain matte screen also -- don't recall it's model designation either. I don't believe any of them are optimized specifically for fast lenses.

 

[benjiboy]

My old F-1s both have the later Laser matte screens. I don't recall the letter designation, but they're plain matte screens in both cameras. The New F-1 has the Partial plain matte screen also -- don't recall it's model designation either. I don't believe any of them are optimized specifically for fast lenses.

There are Focusing screens F.N specifically for fast and slow lenses, I have some of them.