90mm f8 upgrade to 75mm f5.6?

[Rider]

I'm thinking of replacing my Fuji 90mm f8 with a faster 75mm lens. Part of my reason is that the faster 75mm will allow for easier viewing and focusing (without being any heavier or bigger). Am I mistaken in this?

[GSX4]

Rider, I did the same thing. I had a Schneider 90mm SA f8 which I love using, but is a little dark under the cloth. I then was able to source a very nice Rodenstock Grandagon 75mm @ f4.5 The difference is noticeable under the darkcloth. The difference in weight is marginal

[David A. Goldfarb]

Depends on the groundglass. A wider lens is generally harder to view in the corners, even if it's a stop brighter, and this effect can be stronger with a fresnel (depending on the focal length of the fresnel) or with a very fine groundglass that has a strong hotspot.

In general, 75 and 90 are far enough apart that I see them as serving different purposes. I use my 90/8 more than my 75/4.5.

[Walter Calahan]

I'd get the 75, but keep the 90.

Each lens has its unique look and feel. I don't view them an interchangeable.

Down the road you might want to get a faster 90.

Me, I like having as many tools in the bag as possible, so I have a 58, 65, 75, 90 & 120 for my wide 4x5 stuff. It's a sickness. Grin.

[Rider]

I'd get the 75, but keep the 90.

Each lens has its unique look and feel. I don't view them an interchangeable.

Down the road you might want to get a faster 90.

Me, I like having as many tools in the bag as possible, so I have a 58, 65, 75, 90 & 120 for my wide 4x5 stuff. It's a sickness. Grin.

How heavy is your bag (or was it a stroller)? My grand scheme is to replace the 90 with a 75, telling myself I'm being rational and saving money, and then re-purchase a 90, but this time a big fast one (or maybe a Nikon 90 f8).

[E_Aiken]

I can tell you my 72/5.6XL is no easier to focus than my SA 90/8. In really low light, it's actually much harder as the corners are damned near invisible. If ease of focusing is the main thing and you like 90mm, I'd just swap up for a 90/4,5; I think it's a more generally useful focal length anyways - I'm probably going to do this myself in the not distant future.

[Brian Ellis]

All other things being equal, it's probably pretty much a wash. Wider angle of view = dimmer edges and corners. Larger maximum aperture = brighter edges and corners. By exactly how much in each case I have no idea but it doesn't seem like you'd be gaining a whole lot going with a wider angle and only a one stop larger aperture.

[Walter Calahan]

Jogging strollers rule in LF!

[Rider]

I sometimes forget how sharp large format lenses can be! I took a few frames with the Fuji 90mm f8 this weekend, and it is one sharp lens. I think I'll be keeping it; I just won't use it when it's too dark or I'm in a hurry and don't have time to compose and focus properly.

[Carsten Wolff]

Go with David and Brian's advice. "Brightness" depends on many variables....
Also, I wouldn't call a 75mm an upgrade, just a different focal length. I've got both fl (90/6.8 Grandagon-N and old Angulon, 75/4.5 SW Nikkor). When I want to save weight I either just take one lens (or Angulon + Nikkor); when I really want to save weight I only take the vintage glass, i.e. in 90mm the Angulon.

Go get/make yourself a good darkcloth. :)

[davidb]

why not get the Rodenstock or Caltar 90mm 4.5 ?