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

[Alan Klein]

Holy smokes!! Everytime I think I ask a "simple" question, you guys manage to blow it up into all kinds of detail I could never imagine existed!!

So, the question was, "Is it a linear progression between 90mm and 150mm?"

And the answer is........wait for it.......No.

If it were a YES, the answer would be 120mm but John Layton clearly shows us that it's not exactly linear, but, it's really close.

Not to make this thread totally blow up, but based on the math John shows, the divergence from a linear line would become more and more noticable as you get longer in the FL. So I think the 50mm to 90mm is probably pretty flat on the curve and between 90 and 150 is when the progression starts to be noticable, but somewhat negligible and I'm imagining that between 150 and 300 it's real, and certainly by 450 is probably substantial.

Anyone want to plot a graph?

��

I bet you're sorry you asked. We sound like a bunch of digital pixel peepers

When I started 4x5 photography for the first time early last year, I bought in quick succession a 150, then a 75, 90 and 300. Now my back hurts and I cannot carry all the stuff in my kit. My suggestion is to shoot with the two you got and see where you experience takes you. You may find out one in the middle is too much and you'd rather get a 240 or who knows? Get a feel for what the lenses are doing for you first, in any case.

[Drew Wiley]

From a practical standpoint, the lens manufacturers already plotted this for us in terms of their given focal length selections in any given series. They mainly made what was in demand, and the abundance of certain focal lengths on the used market today largely reflects that convention. Why so many 90's, 150's, 180's, 210's ? When my brother went to Brooks photo academy, which was a somewhat expensive school and many had a limited personal budget, they'd tell the students to just get a 90 WA for architecture, and a 210 for portraiture and product shots; then after they had some serious income flowing in, branch out the selection if necessary. It was good advice, and involved not only useful angles of view relative to common projects, but consideration of realistic image circles for 4x5 film.

After awhile, one settles into a certain way of composing things. My own gravitation has been to longer lenses, and after about 10 years of using a 210, decided 250 was my own notion of "normal" (forget the diagonal rule - I'm speaking of the focal length I most often reached for as my preferred personal field of view). On a long backpacking trip, I think I could do almost anything I needed with just 200 and 300 Nikkor M's. But the past couple of decades, it has generally been 180, 250, and 360 Fuji A's. As I get deeper into my 70's, it's likely to be 6x9 roll film backs with 105, 200, and 300 Nikkor M's, or a 125 Fuji W instead of the 105M if I also have some 4x5 holders along. I'm not necessarily recommending this selection to others. We all see things a little differently, and this is just an example of how the ball detents in my own head seem to most comfortably click into position, at least with respect to 4x5 field camera usage. It just feels right for me personally.

[Bernice Loui]

It was recommended to me decades ago during the first ventures into 4x5 two focal lengths, 90mm and 210mm. Those two focal length worked GOOD for the vast majority of 4x5 image marking needs. Eventually added a 135mm and 300mm. That pretty much covered all that was needed unless something very special was needed.

These days the most commonly used focal lengths for 5x7 is much the same:

115mm f6.8 Grandagon, 165mm f6.8 Angulon, 10" Commercial Ektar or 240mm Xenar or 12" Commercial Ektar, 16.5" or 19" APO artar.

This will do for 90+ % of images made these days. Exceptions are when something special is planned and demands other focal lengths which are swapped out as needed.

IMO, this discussion is much about learning what image perspective is relative to lens focal length -vs- camera position. This is a very basic photography skill that MUST be mastered as part of learning what composition should be. Again, IMO zoom lenses so common to digital and 35mm roll film formats often makes for image making habits that do not translate well for LF image making.


Bernice

[John Layton]

Adam...you'd mentioned that the amount of "deviation from linear" would be greater and greater as FL increases. While this may be true in numerical terms, do keep in mind that, when this "greater" deviation value is considered in proportion to the increasing focal length values, the net change of this deviation should be negligible. Make sense?

Hmmm...(scratching head ) - then again, this works both ways, doesn't it? In other words...while the numerical deviation changes in both directions - the actual (proportional) deviation must also, because we had to start someplace. Still, it does seem somewhat "safer" to use, as a starting value, a shorter focal length and move upwards, rather than a longer one and move downwards...which would kind of put the kibosh on my theory of a possible, proportionally derived deviation constant. Ugh...I'm really confusing myself now!

[Alan Klein]

From a practical standpoint, the lens manufacturers already plotted this for us in terms of their given focal length selections in any given series. They mainly made what was in demand, and the abundance of certain focal lengths on the used market today largely reflects that convention. Why so many 90's, 150's, 180's, 210's ? When my brother went to Brooks photo academy, which was a somewhat expensive school and many had a limited personal budget, they'd tell the students to just get a 90 WA for architecture, and a 210 for portraiture and product shots; then after they had some serious income flowing in, branch out the selection if necessary. It was good advice, and involved not only useful angles of view relative to common projects, but consideration of realistic image circles for 4x5 film.

After awhile, one settles into a certain way of composing things. My own gravitation has been to longer lenses, and after about 10 years of using a 210, decided 250 was my own notion of "normal" (forget the diagonal rule - I'm speaking of the focal length I most often reached for as my preferred personal field of view). On a long backpacking trip, I think I could do almost anything I needed with just 200 and 300 Nikkor M's. But the past couple of decades, it has generally been 180, 250, and 360 Fuji A's. As I get deeper into my 70's, it's likely to be 6x9 roll film backs with 105, 200, and 300 Nikkor M's, or a 125 Fuji W instead of the 105M if I also have some 4x5 holders along. I'm not necessarily recommending this selection to others. We all see things a little differently, and this is just an example of how the ball detents in my own head seem to most comfortably click into position, at least with respect to 4x5 field camera usage. It just feels right for me personally.

I don't hike, and my back's giving out at 75. I often shoot nearby my car, using my 300mm with my 4x5. It saves packing the gear and tracking across a tick-infested field to get closer. Like you said, everyone has their own needs and preferences. I guess that's why they make so many lenses.

[Tin Can]

I shot only one Pentax 35mm with OE 'normal' 50mm lens for 5 decades, age 7 to age 60

That's how I NOW SEE!

Longer lens for format I find very interesting

What We See Is What We Get

[Michael R]

I kind of feel like OP would benefit from something like the Stroebel book, which is quite comprehensive, covers all of the topics he has asked about and more, and is easy to read.

[Tin Can]

https://www.thriftbooks.com/w/view-c...dition=5365085

I kind of feel like OP would benefit from something like the Stroebel book, which is quite comprehensive, covers all of the topics he has asked about and more, and is easy to read.

[Michael R]

...not that I’m trying to discourage Adam from posting the questions here, of course. I’m just suggesting particularly when starting out it is good to have some quality resources at your fingertips to go along with “live” feedback/discussion like this. Can’t hurt.

[AdamD]

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....