Is it a linear progression between 90mm and 150mm?

[Bernice Loui]

AA's books are good for the "technical" and related aspects of photography. In one of AA's books there is mention of using a viewing card. Simply a card with a cut-out in the ratio of your fit format of choice. By moving this card near-away from a single eye (one eye closed, one eye open) this allows a rough assessment of what a given focal length lens might produce on camera.

The far more refined and developed tool that does this is a director's viewfinder. These are what film and video directors use to determine lens focal length and camera position goals. Consider getting one of these as a viewing tool to aid in lens focal length selection and camera position set up. There might come a time when this tool is no longer needed once enough images are made and enough hard earned experiences gained.
https://www.bhphotovideo.com/c/buy/D...4/N/4028759376


Bernice

That’s really funny comment about reading first, then ask questions....after re-reading the Ansel Adam’s series of books, at least this question came to me when he talked about building a kit. Then when I finally got to the point where I actually had two lenses to look through, it occurred to me to ask if I should expect the mid point between 90 and 150 would actually appear as the midpoint should I try it.

But I hear you....

[Daniel Casper Lohenstein]

I used to carry a lot of lenses for the 4x5 format until I realised a well made 4x5 negative is very generous in maintaining image quality when cropped. I can crop a 90mm view out of what my 75mm lens takes in, 150mm view from the 135mm lens, 300mm view from the 210mm lens. The key thing is to put the camera in the right place for the composition required and then have a lens that at least "gets it all in".

People always think of focal lengths only in terms of getting something into the picture ... To achieve that, I can also move my butt and reposition myself with the camera. Or crop the image.

IMHO, the interesting thing about focal lengths is the change in perspective while keeping the scale of the main subject the same. If I shoot a cactus at 90 mm from a shorter distance, but at the same size as at 210 mm from further away, the volume of the cactus and the volume of the space around it will appear quite different.

Besides: with 210 mm, you can eliminate distracting things. With 90mm you get them into the picture and even enlarge them if they are too close.

[Alan Klein]

People always think of focal lengths only in terms of getting something into the picture ... To achieve that, I can also move my butt and reposition myself with the camera. Or crop the image.

IMHO, the interesting thing about focal lengths is the change in perspective while keeping the scale of the main subject the same. If I shoot a cactus at 90 mm from a shorter distance, but at the same size as at 210 mm from further away, the volume of the cactus and the volume of the space around it will appear quite different.

Besides: with 210 mm, you can eliminate distracting things. With 90mm you get them into the picture and even enlarge them if they are too close.

You're right. This is why you have to be careful shooting wide to capture everything to crop afterward. Perspectives change with each lens. If you miss the right perspective in the camera with a wider lens, there may be no way to capture it by cropping later.

[Corran]

Perspectives change with each lens.

This is incorrect. Perspective is only changed by positioning of the camera. This misconception comes from the inherent moving of the camera when switching lenses to match framing/composition of the lens prior. If you compose a little loose with a wider lens and then crop later, you still have the same perspective regardless.

[Drew Wiley]

But all things might not be equal when it comes to illumination falloff or image distortion, Corran. Longer lenses make sense for more reasons than just perspective.

[Corran]

I have no idea why you are responding to my post regarding misconceptions about perspective vs. lens choice as if I said something about the use or usefulness of longer lenses. Nothing I wrote has anything to do with what you just said.

[Drew Wiley]

Just the notion of cropping from a wider image instead of framing with a longer focal length lens. Nice in theory or conservatively applied, but not always practical in terms of real-world composition. Of course, the more ridiculous comment that comes up is when someone tells you to just walk closer to the subject. Yeah, with a tree in the way, or a cliff a few steps ahead, or a 7000 ft deep canyon in between, or the angle of view totally changed from the preferred position. Just speaking in principle. Don 't take it personal. My posts aren't necessarily rebuttals.

[Corran]

Of course there are practical concerns, like cliffs or what have you. My impression from the previous discussion is cropping, say, a 90mm lens to a 115mm FoV. This is very little change. Of course, cropping from 90mm to a 210mm FoV is a much different situation and wasting a lot of film to boot. I can think of one user who said in the past that he carried something like 10 lenses, at 20-30mm increments. This is just silly, IMO. A couple steps forward or back and maybe a slight crop if needed is a much more reasonable approach, especially if you actually go somewhere with your gear.

For me, I generally do not bring anything between 90mm and 150mm. Usually 58-90-150-240. Anything in between those focal lengths I think is easily gotten with a bit of movement or cropping if needed, though admittedly I greatly prefer composing full-frame as that is the way I "see." If I know I am going somewhere that might need longer or shorter, I bring those as well or instead of the previously mentioned lenses.

[Alan Klein]

This is incorrect. Perspective is only changed by positioning of the camera. This misconception comes from the inherent moving of the camera when switching lenses to match framing/composition of the lens prior. If you compose a little loose with a wider lens and then crop later, you still have the same perspective regardless.

You're right.

[Alan Klein]

Of course there are practical concerns, like cliffs or what have you. My impression from the previous discussion is cropping, say, a 90mm lens to a 115mm FoV. This is very little change. Of course, cropping from 90mm to a 210mm FoV is a much different situation and wasting a lot of film to boot. I can think of one user who said in the past that he carried something like 10 lenses, at 20-30mm increments. This is just silly, IMO. A couple steps forward or back and maybe a slight crop if needed is a much more reasonable approach, especially if you actually go somewhere with your gear.

For me, I generally do not bring anything between 90mm and 150mm. Usually 58-90-150-240. Anything in between those focal lengths I think is easily gotten with a bit of movement or cropping if needed, though admittedly I greatly prefer composing full-frame as that is the way I "see." If I know I am going somewhere that might need longer or shorter, I bring those as well or instead of the previously mentioned lenses.

For example, there's only about 10 degrees difference horizontally between a 75mm and a 90mm in 4x5. (80 degrees vs 70 degrees).