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View Full Version : Thinking about ultra-wide - what focal length?

Toyon
7-Jan-2009, 08:02
I have a 90/8 lens but would like to go somewhat wider. At what point does the focal length make a significant difference? For example is an 80 or 75 much different from a 90, or does it make sense for me to find a 65. I am looking for an equivalent of about 18mm on a 4x5. So that would indicate a 65 right?

Bruce Watson
7-Jan-2009, 08:14
I have a 90/8 lens but would like to go somewhat wider. At what point does the focal length make a significant difference?

Focal length is inversely related to angle of view. (http://en.wikipedia.org/wiki/Angle_of_view) That is, the bigger the angle of view, the smaller the focal length. I personally spaced my lenses so that they give me approx. 15 degree increments of angle of view (along the 5" axis). If you are looking for a specific angle of view, do the math from the URL to get the focal length you need for the film format you are using.

David A. Goldfarb
7-Jan-2009, 08:23
If you want the 4x5" equivalent of an 18mm lens on a 35mm camera, then 65mm is probably in the ballpark, but bear in mind that you get a lot more foreground/headroom on 4x5" than on 35mm, so it's hard to think of any lens as "equivalent," when the shape of the frame is different.

75mm is a significant jump from 90mm, and depending on your camera and the actual lens you are considering, you might find it easier to use than a 65mm. A 75mm on 4x5" feels like a 24mm on a 35mm camera to me, meaning that I would use them in similar situations, where I want a more pronounced wideangle look or an exaggerated near/far effect, as opposed to 90mm, which still feels fairly natural to me. An interior shot with a 75mm lens, for instance, will look more spacious than it actually is in general.

Nathan Potter
7-Jan-2009, 08:47
If you have and use a 90mm on 4X5 a reasonable step is to go to a 75mm. I use a 75mm SW Nikon for a lot of applications that require a near/far kind of perspective. However the wider the angle the more difficult it is to capture the plane of focus in the off axis position on the GG especially when employing swings and tilts. I still not infrequently mess this up by trying to work too fast in the field. Going to 65mm really puts a strain on focusing but that FL or even shorter would be a next step for you - depending on your style of photography.

Nate Potter, Austin TX.

Ole Tjugen
7-Jan-2009, 08:56
I confess to having 47, 65, 75 and 90mm - I got the shortest ones after discovering that I preferred using 90mm on 5x7" instead of 4x5".

Using a 47mm lens is difficult, and puts a strain on both you and the camera. Without bag bellows it's just about impossible, with bag bellows it's only difficult (unless your camera puts a limit on it, of course).

The difference in angle of view from just a few mm difference in focal length increases as the FL decreases, so you will see a BIG change from 90mm to 75mm.

Walter Calahan
7-Jan-2009, 09:10
Having a 58, 65, 75 & 90, I tend to jump to the 65 from the 90 most offend.

jb7
7-Jan-2009, 09:14
seems I should join in the queue for the confessional-

47, 65, 72 and 90, is the list of my venial sins-

I'd go for the 72 next-

j

David A. Goldfarb
7-Jan-2009, 09:23
For the record, I use 55, 65, 75, and 90 on 4x5", but that's reverse order in frequency of use.

Ron Marshall
7-Jan-2009, 10:01
I have 55, 75, 90. The 75 permits a bit of front rise, while the 55 has very little. If you feel you will need front rise then go for a 75 or 72, otherwise the 65 would be close to a 19 on 35mm.

knoche
7-Jan-2009, 10:04
Ok, me, too...
For my Wista SP I had 47, 58, 65, 75, 90, 135, 150, 210, and 300 in the past.
Now I have 65, 90, 135, 180, 210, and 300 and find that's about right for me.
Of course your subjects and style, etc will result in different choices.

Double the focal length steps is a bit too much so I like one step in between.
Much wider than 65 is, as others have mentioned, a practical problem - very hard to use even without any movements and with a monorail studio camera, with a field camera almost unusable. The bellows draw is so short... and even with bag bellows its a pain. I sold both of the wider lenses as they just didn't see much use, too much hassle, for not much benefit. I really like the 65, though. The 65 and 90 see more use than any of the other lenses but that's just me.
Unless you are doing interiors with very little working space you are perhaps better off just moving back a bit.
I should also throw in that the optical design challenges of wide angle lenses forces some compromises and often the field isn't as flat as we would like or there is some other shortcoming/aberration. Many think that the apparent depth of field will save them but image quality often suffers in the end. Wide angle lenses, especially ultra-wide, are a tougher challenge for the lens designer than std or telephoto, in many ways. Just like everything else in life, you can't have it all - choosing one thing means giving up something else. Pick what matters most and live with the rest.

7-Jan-2009, 10:08
I have a 65 and 75. The 65 is REALLY wide or seems that way to me. The 75 is a nice wide angle and its easier to use on my Tachihara without a recessed board, so I typically choose it.

I find it difficult to compare the 4X5 wide angle to a 35mm wide angle because of the difference in ratios. By diagonal FOV, the 75mm sees like a 21mm on 35mm format. By the short side, it sees like a 18mm and on the long side it sees like a 24mm.

mccormickstudio
7-Jan-2009, 12:24
Depends on what you're shooting. Wider than 65mm I would only use for landscape photography, where the distortion can enhance the resulting image. Shooting architectural subjects, I think 65mm starts to distort the features, but remains acceptable (especially for tight interiors). I've rented the 47mm for architecture and didn't like the results or the fuss (could barely focus it with recessed lensboard on my sinar, tweaking my head over the rail). And if you're on a budget, the earlier super angulon 65mm can be found very inexpensively.

neil poulsen
7-Jan-2009, 12:51
75mm is a significant jump and definitely gives a different view. It also allows more movement than a 65mm.

I'd get the f5.6 or larger versions of whatever lens you get. I wouldn't mess with the f8 or f6.8 versions. They're sharper, and they offer greater movement.

walter23
7-Jan-2009, 13:23
The math is like this.

A = angle of view in degrees. FL = focal length. 127 in both cases is the long dimension of 4x5 (ie, 5 inches in millimeters). You can replace it with 36 for 35mm. Or with the diagonal of your format if you prefer the diagonal angle of view.

a = 2 * atan(127/(2*FL)) * 180 / 3.14159

FL = 127/(2*tan(a*3.14159/(180*2)))

If you have python you can fire it up and run:

import math
FL = 75.0 # focal length - replace with your own
a = 2 * math.atan(127/(2*FL)) * 180 / math.pi
print "Angle of view: ", a

or:

import math
a = 90.0 # angle of view - replace with your own
FL = 127/(2*math.tan(a*math.pi/(180*2)))
print "Focal length: ", FL

Again, replace the number 127 with the dimension of your format (60 for 6x6, 36 for 35mm, etc).

Toyon
7-Jan-2009, 15:02
I was looking at a 72mm super angulon. A little wider than a 75 and it has enormous 221mm coverage. Can anyone give a review of this lens? Thanks for all the feedback.

jb7
7-Jan-2009, 15:28
The 72 has more coverage than is good for most pictures-
it is incredibly wide-

If you use the outer edges, and shoot chromes, you'll need a centre filter too-
I'd use it for any picture with movements,
though others say you don't need it at all-

It's not small, though not incredibly large or heavy either-

If you think you want it, you wont be disappointed-

j

timparkin
7-Jan-2009, 15:59
The math is like this.

A = angle of view in degrees. FL = focal length. 127 in both cases is the long dimension of 4x5 (ie, 5 inches in millimeters). You can replace it with 36 for 35mm. Or with the diagonal of your format if you prefer the diagonal angle of view.

a = 2 * atan(127/(2*FL)) * 180 / 3.14159

FL = 127/(2*tan(a*3.14159/(180*2)))

If you have python you can fire it up and run:

import math
FL = 75.0 # focal length - replace with your own
a = 2 * math.atan(127/(2*FL)) * 180 / math.pi
print "Angle of view: ", a

or:

import math
a = 90.0 # angle of view - replace with your own
FL = 127/(2*math.tan(a*math.pi/(180*2)))
print "Focal length: ", FL

Again, replace the number 127 with the dimension of your format (60 for 6x6, 36 for 35mm, etc).

Heh... nice to see Python being used!!

As a bit of a short cut, I wrote the following spreadsheet to calculate various lens ratios and spreads.. feel free to use as you see fit

Tim

Lachlan 717
7-Jan-2009, 17:27
Can anyone provide their thoughts on 75mm versus 80mm SSXL?

Thanks,

L

Brian Vuillemenot
7-Jan-2009, 20:05
I use a 58, 75, and 110, with the 110 being used more than both the 75 and 58 combined. To me, it's a nice spread of wide lenses. If you have a 90, you might want to go for a 65 and perhaps even a 47, if you're into the super-mega-ultrawide thing.

Eric Woodbury
7-Jan-2009, 21:33
Get the 58mm and then, if it is too wide, just crop. That's what all that neg is for.

I had a 90mm and decided it just confused me, so I sold it. Now I have the 72, 110, 150 and up for 57 and 58, 110, 180 and up for 45. 90s are trouble.

walter23
7-Jan-2009, 23:29
90s are trouble.

Heh, that's a weird opinion to have of one of the most commonly-used wide angle focal lengths.

timparkin
8-Jan-2009, 02:33
Heh, that's a weird opinion to have of one of the most commonly-used wide angle focal lengths.

Never mind 90's ... 135's Hubble and Bubble .. Toiling and trouble are nothing compared to that!

Dominique Cesari
8-Jan-2009, 03:05
The 72 XL is wide, but not so much different of a 90. I was very satisfied with a 90mm, which was my first wide lens. But not wide enough for a significant part of architectural work, so I baught a 72XL, and from then on, nearly no more used the 90.

As said, the 72XL has big coverage, needs an expensive center filter with chromes, and is somewhat bulky. It has noticeable curvature of field, which may affect the corners, specially with generous shifts. All in all, for architectural work, it's great. The 80 XL is interesting too, but may ran out of coverage when the 72 XL does the job.

If you want to go really wide, think of a 58 or even 47mm. In my opinion, these ultra-wide are not really landscape lenses, but to use inside buildings.

Wally
8-Jan-2009, 20:49
Having a 58, 65, 75 & 90, I tend to jump to the 65 from the 90 most offend.
Same exact wide angle list. And like you, my 75mm isn't getting the use I thought it would.

Wally
8-Jan-2009, 20:54
...
If you have python you can fire it up and run:
...

Wow! Another pythonic photographer!

Jim Michael
9-Jan-2009, 16:21
No snake handling required. Google 127/(2*tan(90*pi/(180*2)))