Is a 40mm lens the sweet spot?

[noimmunity]

Originally Posted by back alley

where on ebay...can't find it.

I sent you a pm, Joe.

[BTMarcais]

Originally Posted by Karefin

Anyway, that diagonal is 43mm, so a 45mm (for example the Contax G 45/2 Planar) is the closest manufactured, as far as I know.

Pentax makes the FA 43mm f/1.9 limited. One of my favorite lenses.
One of the reasons I still pick up the SLR's sometimes. It is a really comfortable focal length to use I find.

They also made a limited edition of this in leica thread mount, came with a VF with 43 and 50mm brightlines.

-Brian

[Karefin]

Originally Posted by kshapero

Suddenly I hear more and more about the 40mm lens is the sweet spot and 50mm became the standard via an accident by Barnack in the 30's. My typical kit has been 21-40-90, although I am sneaking in the 75mm more and more. Others's thoughts? I almost consider 50mm as a very short tele these days.

I like your combo! Mine is currently 21-40-135 and I have considered only minor changes if I had all the money. The 40 as a focal length seems best for me in the normal range because with the 50 I normally have to get ackwardly far from people when I'm shooting them. Especially since I don't have a 28 for example. The 50 also results in a bit too teleish perspective for that purpouse.

I also endorse the "more normalness" of 40. The Pentax 43 might be fun to try, but I doubt I'll bother to go through all the trouble and money of changing. A limited edition lens? Not for me, thanks.

[zenlibra]

40mm feels "normal" to me as well. Everything I want to shoot frames nicely in a 40mm frameline.

I use 21mm, 40mm, 50mm, and 85mm.

[Tom A]

A bit of absolutely useless trivia: Barnacks's first camera (35mm) was supposedly made while he was working for Zeiss. He took the prototype along when he started working for Leica and it became the basis for the Ur-Leica and it has a 42 mm Zeiss Milar lens on it.
Supposedly the 50mm f3.5 Elmax (Max Berek design) was easier to correct and thus became the basis for the 50mm "normal" lens.
The 40f1.4 Nokton is one of my favorite's for a one camera/one lens kit. Stick it on a M2 and use the inside frame of the 35 lines and it works fine. On the M3 I use the outside of the 50 frames - close enough for me. Rangefinders are not an exact science anyway when it comes to framing.

[Doug]

Originally Posted by Trius

...Edit: And yes, 40mm is THE sweet spot for "normal". 28, 40 and 60-ish make a great combo. Too bad no one makes a 60mm any more; the Helios 44M (M42) is no slouch for SLR.

A useful combination, I agree. There is the 60mm Hexanon, and again for SLR the current 58mm f/1.4 Nokton.

If we push a 28, 40, 65 grouping into 6x4.5cm format, it comes out about 45, 65, and 100mm. Coincidentally those are the three lenses last offered for the Bronica RF645.

I like the 40-ish region for general-purpose carry and I'm fortunate to have lenses around 55°-60° angle of view for formats from half-frame to 6x7. Indeed a "sweet spot"!

[BTMarcais]

somehow I've ended up with: pentax 43mm f/1.9, pentax 40mm f/2.8 M (the older manual focus, not the digital pancake), rollei 35T w/ 40mm f/3.5, and the contax G45 f/2. The 40-45 range just seems much more comfortable for me than a 50.

[sleepyhead]

Originally Posted by Doug

A useful combination, I agree. There is the 60mm Hexanon, and again for SLR the current 58mm f/1.4 Nokton.

If we push a 28, 40, 65 grouping into 6x4.5cm format, it comes out about 45, 65, and 100mm. Coincidentally those are the three lenses last offered for the Bronica RF645.

I like the 40-ish region for general-purpose carry and I'm fortunate to have lenses around 55°-60° angle of view for formats from half-frame to 6x7. Indeed a "sweet spot"!

I guess 75mm lenses on 6x6 are closer to "normal" than 80mm lenses?

[ampguy]

43mm is it. 40mm is close.

[ray*j*gun]

Tom, what about on an M6?

The 40f1.4 Nokton is one of my favorite's for a one camera/one lens kit. Stick it on a M2 and use the inside frame of the 35 lines and it works fine. On the M3 I use the outside of the 50 frames - close enough for me. Rangefinders are not an exact science anyway when it comes to framing.[/quote]

[Daneinbalto]

To return to what a former poster brought up - from where originates the notion that a focal length corresponding to the frame diagonal is "normal"?

I understand that the frame diagonal is how one determines lens equivalents across various formats. For example, the diagonal of the 35 mm negative is 43 mm. If you cut that negative in half, as in a half-frame camera or APS-C, the diagonal is 28 mm - not as you might have expected 22 mm (43/2). Thus, when you go from 35 mm to half-frame or APS-C, the equivalent of a 43 mm is 28 mm, not 22 mm.

But why should there be a 1:1 relation between the diagonal and what is considered a normal lens? Why wouldn't the normal lenses on the two formats be a multiple of the frame diagonal, say, 47 mm and 31 mm? (diagonal x 1.1) or a power of the diagonal, say, 50 mm and 32 mm (diagonal to the power of 1.04)?

Maybe the Wikipedia entry that states that film diagonal = normal lens should be modified to reflect the arbitrary nature of the 1:1 relation.

Unless someone can show that humans, at least when they are young, have a 1:1 relation between the diagonal of their field of view and the focal length of their eyes.

[back alley]

what is the field of view of the average human?

[nightfly]

40mm is neither here nor there for me. It's not quite wide enough for street and not quite tight enough for casual portraits. It's the Goldilocks of lenses.

I much prefer a 35 as a standard lens. I sold a prefectly good 40mm Summicron so I could spend almost 3 times as much on a 35 Summicron and don't regret it one bit. Tonality is the same but the field of view is much more useful.

[NickTrop]

Eh - thumbs down on the 40. Wide enough to distort faces closer in, so you can't use it for portraits. Not wide enough to matter. Get a go 50 (or 45) and take 1 step backwards.... there's your 40.

[Frankie]

I have an arsenal of Nikon F/F2/FM2/FM3A and 22 lenses, but I use the CV 40mm/1.4 with my ZM as the one-lens travel outfit. I filed down a claw on the mount to bring up the 35mm frame line which is a tight ~95% frame...Nikon style.

I shot throughout Japan and did not feel I want or need another focal length; 1.4 is handy in low light and the ZM AE is spot on...so pick an aperture, preset and just shoot. I used Tri-X rated at ISO 250, so f8 or 5.6 most of the time.

[ampguy]

on where the point(s) of focus the eye is at, and how much peripheral vision you want to include in the definition of "field of view"

FWIW, I have read books and studies that cite 35mm, to 105mm, the most common 50mm, but to me, the most compelling, 43mm.

Originally Posted by back alley

what is the field of view of the average human?

[Doug]

Originally Posted by Daneinbalto

To return to what a former poster brought up - from where originates the notion that a focal length corresponding to the frame diagonal is "normal"?

It might be useful to work back from the end result: A print on display. Let's suppose a gallery show... The theory has it that the "best" viewing distance for a print is when the eye's angle of view matches the angle of the lens making the image, adjusted for any cropping. So, you'd stand closer to a wide-angle shot than a telephoto shot. For a print made with a 28mm lens on 35mm film, for instance, you would move in so that the corners form a 75° angle with the eye. For a print made with an 85mm lens on 35mm film, you would stand back so that the corners form a 28° angle with the eye.

This would give the most "natural" viewing perspective, and some print makers size their prints to encourage this, and it may be kept in mind in hanging the show. For instance, a largish wide-angle print hung in a place where the viewer cannot back away, encouraging the "proper" distance.

So why would viewers need to be influenced or forced into the appropriate viewing distance? Because of another factor, now zeroing in on the question at hand...

It turns out that for most people with normal eyesight, the most comfortable viewing for a rectangular flat artwork is from a distance about equal to the object's diagonal. So people tend to position themselves (or hold the item) accordingly.

Using a trigonometric approach, imagine a triangle where the distance from one apex to the opposite side is equal to the length of that opposite side. Bisect the triangle along that distance line. Now to figure the angle at that new apex for which the sine is half the cosine... That's about 26.5°... since the triangle was bisected we need to double that angle to know the original angle of the apex: 53°. Well well, that's the angle of view of a 43mm lens on 24x36mm frame, for which the diagonal is 43mm.

Going at it from the optical approach: The definition of focal length is the distance from the lens's optical center to the film/media/sensor. So if the lens focal length is the same as the media diagonal, that matches the most natural viewing relationship later between eye and print.

[back alley]

so a 28 on the rd1 gives the fov of a 43mm lens, thus it's the 'normal' lens for the rd1?

[Prosaic]

Originally Posted by kshapero

Suddenly I hear more and more about the 40mm lens is the sweet spot and 50mm became the standard via an accident by Barnack in the 30's. My typical kit has been 21-40-90, although I am sneaking in the 75mm more and more. Others's thoughts? I almost consider 50mm as a very short tele these days.

40mm lens:

40 or 50 or 60, these are just numbers. I am getting better results the longer I use one lens exclusively, regardless of focal length. After a week, maybe after a month, you´ll see how versatile a 21mm lens really is.

[Prosaic]

Originally Posted by Frankie

I have an arsenal of Nikon F/F2/FM2/FM3A and 22 lenses

Wow, I wonder why some photographers gather that lot of equipment, most of which they probably never touch for years. Owning less lenses makes it far easier to pick one for a walk.

[Karefin]

Originally Posted by Doug

It might be useful to work back from the end result: A print on display. Let's suppose a gallery show... The theory has it that the "best" viewing distance for a print is when the eye's angle of view matches the angle of the lens making the image, adjusted for any cropping. So, you'd stand closer to a wide-angle shot than a telephoto shot. For a print made with a 28mm lens on 35mm film, for instance, you would move in so that the corners form a 75° angle with the eye. For a print made with an 85mm lens on 35mm film, you would stand back so that the corners form a 28° angle with the eye.

This would give the most "natural" viewing perspective, and some print makers size their prints to encourage this, and it may be kept in mind in hanging the show. For instance, a largish wide-angle print hung in a place where the viewer cannot back away, encouraging the "proper" distance.

So why would viewers need to be influenced or forced into the appropriate viewing distance? Because of another factor, now zeroing in on the question at hand...

It turns out that for most people with normal eyesight, the most comfortable viewing for a rectangular flat artwork is from a distance about equal to the object's diagonal. So people tend to position themselves (or hold the item) accordingly.

Using a trigonometric approach, imagine a triangle where the distance from one apex to the opposite side is equal to the length of that opposite side. Bisect the triangle along that distance line. Now to figure the angle at that new apex for which the sine is half the cosine... That's about 26.5°... since the triangle was bisected we need to double that angle to know the original angle of the apex: 53°. Well well, that's the angle of view of a 43mm lens on 24x36mm frame, for which the diagonal is 43mm.

Going at it from the optical approach: The definition of focal length is the distance from the lens's optical center to the film/media/sensor. So if the lens focal length is the same as the media diagonal, that matches the most natural viewing relationship later between eye and print.

Thank you, Doug! Now I'm getting a hang of it... When you have a field of view which you don't have to crop or expand at all; you have in your view what you need to see, nothing more, nothing less - that's "natural", because you can't zoom with your eyes.

And the analogy for the lens "viewing at the picture" so that it is most natural for it, was very enlightening.

Now we all can imagine the framelines of a 40-45 mm to our fields of vision, plus some tele, some wide-angle ones too...

[George Bonanno]

An image from a 45mm lens projected on 35mm film using a full frame still camera is the perfect complement to human vision. Any other focal length is a distortion of reality.

"Contort Yourself"... James Chance

[Kent]

Yes, 40mm are great with RF cams and with my DSLR (1.6crop) I love the 24mm lenses (~ 38.6mm) - I wonder why.

[ampguy]

The fov of 43mm would be close to what I consider a "normal" view. But if you open your other eye, and look forward in the same direction with both ones, one in VF with 43mm fov, you'll notice that you're cutting off peripheral vision.

But from a lens, distortion, compression perspective, the 28mm has more of it than a 43mm, or even a great 35mm. I've always liked the fov of a 40 on the RD1, and while seemingly a tighter than "normal" fov, it has less distortion than a wide 28 (for example, look through the rf with 28 while standing, and rotate the camera from the ground to different angles, and you'll see distortions that your other eye won't, as your brain corrects for it.

A side note, since you're using the RD1, is that a 40 fits the 35mm framelines very well, probably better than a 35 at many subject distances.

Originally Posted by back alley

so a 28 on the rd1 gives the fov of a 43mm lens, thus it's the 'normal' lens for the rd1?

[ampguy]

but unrealistic. I look at gallery photos from a few feet away, prints in books about 12" away. Images on monitors about 12-18" away. That isn't going to change.

Originally Posted by Doug

It might be useful to work back from the end result: A print on display. Let's suppose a gallery show... The theory has it that the "best" viewing distance for a print is when the eye's angle of view matches the angle of the lens making the image, adjusted for any cropping. So, you'd stand closer to a wide-angle shot than a telephoto shot. For a print made with a 28mm lens on 35mm film, for instance, you would move in so that the corners form a 75° angle with the eye. For a print made with an 85mm lens on 35mm film, you would stand back so that the corners form a 28° angle with the eye.

This would give the most "natural" viewing perspective, and some print makers size their prints to encourage this, and it may be kept in mind in hanging the show. For instance, a largish wide-angle print hung in a place where the viewer cannot back away, encouraging the "proper" distance.

So why would viewers need to be influenced or forced into the appropriate viewing distance? Because of another factor, now zeroing in on the question at hand...

It turns out that for most people with normal eyesight, the most comfortable viewing for a rectangular flat artwork is from a distance about equal to the object's diagonal. So people tend to position themselves (or hold the item) accordingly.

Using a trigonometric approach, imagine a triangle where the distance from one apex to the opposite side is equal to the length of that opposite side. Bisect the triangle along that distance line. Now to figure the angle at that new apex for which the sine is half the cosine... That's about 26.5°... since the triangle was bisected we need to double that angle to know the original angle of the apex: 53°. Well well, that's the angle of view of a 43mm lens on 24x36mm frame, for which the diagonal is 43mm.

Going at it from the optical approach: The definition of focal length is the distance from the lens's optical center to the film/media/sensor. So if the lens focal length is the same as the media diagonal, that matches the most natural viewing relationship later between eye and print.