Opinion: Would a 90mm f8 or f6.8 lens be too dark for dawn and dusk landscape?

[cirwin2010]

I'm starting to move over to large format to medium format landscape photography. I almost exclusively shoot black and white with the end goal of producing a silver gelatin print (up to 16x20"). My most commonly used lens for landscape type work in medium format is a 50mm-55mm f4.5 so I would be looking at getting a 90mm for a wide angle.

I like to get up to shoot a location well before the sun comes up so I can catch the early morning glow (and to avoid people). I am often setting up while the first hints of morning light start to show and I usually leave once the sun is fully over the horizon.

My current lens is a 161mm f4.5 which I found to be extremely difficult to compose and focus on my Calumet cc-400 ground glass. I replaced the ground glass with a "cheap" fresnel lens off ebay which has aided greatly, but isn't perfect. I am on a wait list for a Chamonix fn-2 which I assume will have a much brighter and nicer viewing experience.

Ideally I would like to get an f8 (or f6.8) lens for size, weight, and cost over a f5.6/f4.5 90mm lens. I am a bit concerned that the ground glass experience (even on the Chamonix) may be a bit too dark for my use case, but I wanted to hear what some people thought about it.

[Greg]

For ultra WA work I use a 90mm f/5.6 Schneider Super-Angulon XL on my whole plate Chamonix, and a 5.9" f/14 No. 5 Gray Periscope on my 11x14 Chamonix. The XL has a central ND filter on it that I prefer not to remove (for simple fear of accidentally dropping it). The Gray does open up to f/10 for focusing only. I have no problem using both cameras after sunset, I like the quality of light at that time. I am only using the OEM Chamonix GG. I did adapt a fresnel to the 11x14 (at no small expense), but found it more difficult to focus with it on. The "ridges" of the fresnel interfered with image on the plain GG. Loupe does matter - I use a large very bright Pentax loupe. You won't run into this before sunrise, but after sunset the ambient natural lighting can get really dark very fast, so I always have a small LED headlight on hand and use it a lot when breaking the equipment down.

[Jody_S]

Depends on your eyesight. I've had no issue focusing f16 lenses indoors in abandoned buildings, but I have exceptionally good night vision. Some people seem to need the f4.5 of some LF plasmats to focus outdoors.

[LabRat]

Depends... A good new GG helps a lot, but one can get used to dim old lenses with a good focusing cloth...

But most important is allowing enough time for your eyes to properly dark adapt in darkness before viewing GG... A minute or two under cloth without peeking outside allows eyes to adjust...

In normal daylight, wearing dark sunglasses before getting under the cloth speeds up light adaptation a bit...

Steve K

[maltfalc]

spend some of the money you'll save on a laser pointer or bright, focusable flashlight.

[Oslolens]

spend some of the money you'll save on a laser pointer or bright, focusable flashlight.

And consider prefocusing the day before.
Laser may be subject to regulation where you live...

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[cirwin2010]

And consider prefocusing the day before.
Laser may be subject to regulation where you live...

Sent fra min SM-G975F via Tapatalk

Prefocusing the day before is not really an option for me with how I plan my trips (short couple hour trips for now). Shining a light on my subject at night sounds pretty amusing but may actually work for a few scenes, though I'm not sure I'm brave enough for that for some others.

[djdister]

Create your own infinity stops and shoot at f/16. All you need is a flashlight to set your focus at the infinity stop (or other preset hyperfocal distance) and set the f stop and you're done.

[Mark Sampson]

A good loupe (low-magnification but a large eyepiece) might help. Many loupes have too much magnification; you don't need 7x to see a groundglass.
On the rare occasions I've made photographs in similar situations to what you describe, I was able to focus on the skyline, which gave me (effective) infinity. I've always used 90/8 lenses, a faster lens might have helped. But I'd just buy a lens and give it a try. Practice makes perfect!

[Kiwi7475]

Let’s see…. Yes I find F8 too dark to focus reliably in low light conditions. F5.6 is much better. I don’t typically use many f6.8 lenses in those situations. And I have a good and bright fresnel.

Focusing during sunset is easier because you start from more light to less light and if you arrive a little early you can focus no problem and then shoot as dark as you want. You can even rotate or point elsewhere and you don’t need to refocus, assuming you’re not changing drastically the distances involved. I routinely shoot for example with a foreground element and then tilt to get the infinity background in focus and if I roughly keep proportions I can just te-point and shoot even when it’s really dark.

Focusing at sunrise it trickier because you start with less light and by the time you have enough to focus your sunrise colors are gone. It’s a race against time. You can try and play safer by using smaller apertures than you’d normally need. Plain out of focus is worse than diffraction limited!

I’ve tried strong flashes, and laser pointers. Don’t work for me if you have complicated scenes that require tilting. YMMV.