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nray
31-Oct-2006, 07:39
Hi.

I have just entered LF world having bought a 4x5 camera which came with a Xenar 5.6/150mm lens. Previously I had a medium format (6x6) camera and shot portraits and landscapes with it. The Large Format world is a new world and I am feeling a bit lost. I have been studying and researching but there is a ton of stuff to learn. I also shot 35mm landscape and portrait. My favorite landscape lens there was a 28mm. I would like a similar landscape lens for Large Format that will produce a nice panoramic but not be too wide that things seem miles away. I have been looking at Schneider lenses. I now have in mind a Super-Symmar XL 110/5.6.

I have some questions. I have thought that the lens size in mm would tell me the angle of coverage it had. In Large Format this doesn't appear to be the case. The angle of coverage can vary widely. So, what do I want to look at, the angle of coverage or the lens in mm? If I look at the angle of coverage, the 110mm lens would seem to match pretty good with my old 28mm lens. I have also read that too wide a lens will loose sharpness at the edges. What part would the lens image circle play a part in helping in my decision? I am having a hard time understanding the angle of view and it's relationship to the image circle.

The other lens I am looking for is a portrait lens. I have decided on a APO-Symmar/5.6 210mm, which I'm sure would be a great landscape lens also.

If anyone cares to wade into this, I would appreciate any advice or recommendations.

Thanks.
Norm Ray

Nick_3536
31-Oct-2006, 07:55
A 110mm lens is a 110mm lens. Unless you like variety no reason to buy two 110mm. Maybe if you want a light weight one and bigger one. But like I said 110mm will be 110mm.

Angle of coverage is the back end. You really want to look for angle of view. The problem is the lens companies can't know what format you'll stick that lens on so they don't tend to publish angle of view. Between roll film holders and the fact some lenses can cover much larger formats it's possible the same lens will be a long and a very wide lens.

On 4x5 a 150mm is like a 80mm on 6x6. If you just double the focal lengths you like on 6x6 you'll get close to what you need for 4x5.

Ron Marshall
31-Oct-2006, 08:01
Norm, 35mm has a diagonal of 43mm. 4x5 has a diagonal of 153mm.

To find roughly which focal length in 4x5 corresponds to 28mm on a 35mm camera, multiply 28mm by 153 then divide by 43. Which is about 100mm, so a 90mm or a 110mm would be close.

Above I wrote roughly corresponds; this is because 35mm is more rectangular than 4x5. Because 35mm is wider the 90mm on 4x5 would be a better match.

The angle of view for a lens (not the angle of coverage, which is greater to allow for movements) can be calculated with a little trigonometry.

The width of the exposed area of film is about 120mm. Half of that is 60mm.

For a 150mm lens the distance between the lens and film is about 150mm (may not be, but for simplicity lets assume)

The horizontal angle of view = 2 Arctan (60/150) = 43.6 degrees

photographs42
31-Oct-2006, 08:27
If you like 28mm on a 35mm camera, the technically equivalent would be roughly a 85mm in 4x5. But the aspect ratio of 4x5 is different so the 85 won’t feel the same. I think the 110 XL is a bit of overkill for 4x5 plus a 75mm or 90mm would be closer to your 28mm for 35.

The diagonal of 4x5 is about 154mm so you need a lens with an image circle larger than that to allow for movements but almost any 75 or 90 will have enough coverage (image circle). As Nick said, the focal length is the focal length. The angle of coverage determines the image circle. Because on a view camera you can shift the front or rear standards, the image circle has to be larger than the film rectangle. Think of it as moving the rectangle that represents the film around in the circular projected image.

I’m not a portrait guy but I would think you would want something around a 210mm or 300mm for that.

Jerome

steve simmons
31-Oct-2006, 08:30
There is a lot of information in the Free Articles section of the View Camera web site that will be helpful to you

Angle of coverage is dependent on how the lens is designed. It has nothing to do with focal length or format size.

Angle of view is a function of the focal length of the lens and the size of the film.

Newer wide lenses will not lose sharpness at the edges. Some of the older ones will.

There are several books that might help

User's Guide to the View Camera by Jim Stone, Large Format Nature Photography by Jack Dykinga or Using the View Camera that I wrote. Check your local library.


steve simmons
www.viewcamera.com

Sheldon N
31-Oct-2006, 08:36
The 110mm Super Symmar XL would be a very nice lens as a moderate wide angle for landscape photography. It is very well regarded both for optical performance and for the large image circle that it provides. It is however an expensive lens, primarily because of the large image circle.

The image circle is the diameter of the cone of light projected out the back of the lens (angle of coverage). The size of the cone of light is independent of focal length - instead it is a function of lens design. What this means is that you can have a 110mm lens that will just cover a piece of 4x5 film, and a 110mm lens (like the 110mm SS XL) that will cover the size of an 8x10 piece of film - and both lenses will provide the same field of view when used on 4x5. It is only when you want to add movements or use a larger piece of film that the added coverage comes into play.

So, you choose what lens focal length you need first, using the lens length in mm. Then you choose a specific lens based on your needs for the intended format (4x5, 5x7, 8x10) and/or your need to be able to apply strong movements such as shift/rise. The way to judge whether the lens design will serve your needs is by looking at either the angle of coverage (angle of the cone of light coming out the back of the lens) or the image circle in mm. More angle of coverage/larger image circle = more ability to use movements or use a larger film format.

If budget is a concern, you could save a fair bit of money by choosing a lens with less coverage than the 110mm SS XL. Landscape photography in 4x5 doesn't require that much image circle (200mm of image circle is more than enough), so the almost 300mm of image circle that the SS XL provides can be overkill. Other alternatives to the 110mm might be a Schneider 120mm APO Symmar or a Fujinon 125mm. If budget isn't a concern, then the 110mm SS XL is a dream lens.

For a portrait lens, something a little longer would be ideal. I'm guessing that you meant to type APO Symmar f/5.6 210mm, rather than 110mm - primarily because there is no APO Symmar 110mm. The APO Symmar 210mm would be a very nice lens, lots of coverage and a top performer, and a good focal length for portraits. Again if budget is a concern any 210mm f/5.6 from Rodenstock, Fuji, or Nikkor would perform pretty much just as well, at maybe half the price. The APO Symmar is at the top of the list, though (along with the Rodenstock APO Sironar S).

Good luck on your choices!

paulr
31-Oct-2006, 08:41
It probably depends on how you see and what you photograph, but for me comparing formats based on the horizontal dimension has been more accurate than the diagonal.

The horizontal measure fits my sense of how "wide" the view is. The vertical dimension has been more about general proportion and emphasis on foreground, etc..

Based on this, to me a 110 lens in 4x5 feels pretty close to a 35mm lens in 35mm (keep in mind that unless you print full frame with the funky black borders, your printable width with 4x5 is a bit less than 5 inches, making the effective focal length even longer). Your mileage may vary ... but it's worth thinking about what you really look at when picking a focal length.

Bruce Watson
31-Oct-2006, 08:59
http://www.largeformatphotography.info/lenses-primer/

http://www.largeformatphotography.info/lenses/

I think you are confusing angle of coverage and angle of view. In 35mm, these two things are basically the same. A lens needs no more coverage than is required by the 35mm frame, it need not have coverage for movements because there are none.

Someone else gave the formula for angle of view, which basically describes the angle of view the film sees. Angle of coverage is a design parameter of the lens and is set by the manufacturer. Angle of coverage basically defines the size of the coverage circle which lets you know how much room you have for movements.

A word of warning on lens choice. You favorite lenses for 35mm won't necessarily translate to 5x4. The reason isn't just the difference in aspect ratios. The main reason is that one uses 5x4 differently than one uses 35mm. With 35mm, people almost universally compose with the camera on their face, looking through the viewfinder/rangefinder and "composing with their feet" as it were. This is very difficult to do with most 5x4 cameras (like everything else, there are exceptions). With 5x4, most people walk the scene and compose with their eyes before setting up their tripods. I find I seldom move the tripod once I've decided where to setup -- completely different from the way I used 35mm.

And this technique will redefine which lenses you want, and which are your new favorites. For example, when I was using 35mm I never owned a "normal" lens. With 5x4 I resisted buying a normal lens for years because I never wanted one with 35mm. In the process I missed a lot of good compositions. And it was this process of missing good compositions that forced me to re-evaluate, get beyond my prejudices, and buy that 150mm lens which has now become one of my favorites. I'm just saying...

In the end, you'll have to make your own judgments about lenses. No one else can make those decisions for you. You'll have to find what's most comfortable for you, because if you aren't comfortable with your tools, it's difficult to make good art.

nray
31-Oct-2006, 09:04
So, the image circle is dependent on the design of the lens and not dependent on the size of the lens?

I will get the same image (angle of view)looking through 2 different 110mm lenses on the back of my camera, but the image circle could be twice as big? Right?

Would that decision (of the size of the image circle to get) have an effect on swings and tilts I may want?

I think I'm getting it. Thanks for all your responses. I am very excited about learning this and look forward to getting great shots. Steve, I do have your book "Using the View Camera". I was also told to pick up Ansel Adam's book.

My daughter can't understand why I bought this camera and not the latest digital. To me it's like going to McDonalds or preparing a Thanksgiving dinner at home.

Norm Ray

Nick_3536
31-Oct-2006, 09:07
So, the image circle is dependent on the design of the lens and not dependent on the size of the lens?



Depends on both. A tesar at 150mm will have one image circle. A tesar at 300mm will be twice the image circle. Same design different focal length. OTOH a wide angle design will always have more coverage at the same focal length then a normal design.




I will get the same image (angle of view)looking through 2 different 110mm lenses on the back of my camera, but the image circle could be twice as big? Right?



Could be.




Would that decision (of the size of the image circle) have an effect on swings and tilts I may want?



Usually you work the other way. If you need lots of movements you buy a lens with lots of image circle.

steve simmons
31-Oct-2006, 09:08
So, the image circle is dependent on the design of the lens and not dependent on the size of the lens?

YES


I will get the same image (angle of view)looking through 2 different 110mm lenses on the back of my camera, but the image circle could be twice as big? Right?

YES

Would that decision (of the size of the image circle) have an effect on swings and tilts I may want?


YES. A larger angle of coverage will give you more movements. You may or may not need them.

Ask people who give you camera recommendations what lenses they use and what they photograph. It will help you put their advice in context.

steve

nray
31-Oct-2006, 10:03
The way to judge whether the lens design will serve your needs is by looking at either the angle of coverage (angle of the cone of light coming out the back of the lens) or the image circle in mm. More angle of coverage/larger image circle = more ability to use movements or use a larger film format.

I'm still confused on this. The angle of coverage is the cone of light coming out the back of the lens. So, the bigger this number (the angle of coverage) equates to a wider field of view horizontally? The image circle is then just the frosting for movements?

steve simmons
31-Oct-2006, 10:36
So, the bigger this number (the angle of coverage) equates to a wider field of view horizontally?

You are confusing angle of view and angle of coverage. You are stressing toooo much. Relax. Just look at page 30 of Using the View Camera.

steve simmons

Ron Marshall
31-Oct-2006, 11:22
The cone of light is bigger than the film, that is what allows movements. You can move the film up, down or sideways, as long as it is still within that cone. The angle of the cone is the angle of coverage for that lens.

The angle of view is determined only by the focal length of the lens, simple geometry only.

The angle of the cone (pyramid) that exactly covers the sheet of film is the angle of view.

Daniel Geiger
31-Oct-2006, 13:06
Hope the two angles are clear by now.

I also agree with posters on the difference in focal length equivalent between SRL and LF. The difference in aspect ratio is quite significant; though you can always crop.

Re XL being overkill for landscape, I disagree. I made the transition from SLR to 4x5 a little under 2 years ago. For a wide angle, I first got a Schneider 90 mm SA f/8 with small angle of coverage and ran out of fall/rise quite quickly and upgraded to the 90XL (for same type of images, same "feel", but with more options for movements). I LOVE the 90XL (with center filter).

110's in general will have a greater angle of coverage than a comparable 90, so you will get a bit more movements out of a non-XL 110, than a non-XL 90. Have a look at the 4x5 lens table on the LF home page, most handy reference.

I also concur with another poster re the "normal" lens, i.e., 150 mm in 4x5. I hardly ever use it for SLR, but after databasing the 4x5 images, the the modal class of focal lengths is 150. [my arsenal is 90-150-180macro-210-360-500-720, thinking about a 72/75].

Sheldon N
31-Oct-2006, 13:14
I'm still confused on this. The angle of coverage is the cone of light coming out the back of the lens. So, the bigger this number (the angle of coverage) equates to a wider field of view horizontally? The image circle is then just the frosting for movements?

Angle of coverage is basically the same measurement as image circle, just two different ways of looking at it. The angle of coverage is how wide the image is projected out the back of the lens, which then determines the diameter of the image circle. The angle of coverage is the angular measurement of the cone, and the image circle is just the diameter measurement of a slice out of that cone.

For example a 150mm lens with a 75 degree angle of coverage will generate an image circle of 231mm when the lens is focused at infinity. A 150mm lens with a 70 degree angle of coverage will generate an image circle of 210mm when the lens is focused at infinity.

Angle of VIEW is a different thing. Both 150mm lenses will have the same angle of view when using the same size film format. The combination of film format and focal length is how the angle of view is determined. The only time angle of coverage influences angle of view is when you stick a larger piece of film behind the lens. The 110mm SS XL that is slightly wide when used on 4x5 is quite wide on 5x7, and extremely wide on 8x10. The use of the larger film formats is enabled because the lens' angle of coverage is sufficient (105 degrees) to cover the larger piece of film.

steve simmons
31-Oct-2006, 14:03
The angle of view is determined only by the focal length of the lens, simple geometry only.

Not true. The angle of view for any given lens is determined by the size of the film. A 150mm lens on a 4x5 will have an angle of view of X. That same lens on a 5x7 will have an angle of view of X+ becasue the film is larger and takes in more, in this case, of the image circle.


steve simmons

GPS
31-Oct-2006, 14:11
The angle of view is determined only by the focal length of the lens, simple geometry only.

Not true. The angle of view for any given lens is determined by the size of the film.

steve simmons

Well, uhm, the simple truth is that the angle of view is determined by both the focal length AND the size of the film...well, uhm, ;-)

steve simmons
31-Oct-2006, 14:16
Here is what I said in an earlier post

"Angle of view is a function of the focal length of the lens and the size of the film."

If people have a copy of Using the View Camera look on page 30. There is a diagram that shows the difference between angle of view and angle of coverage.


steve simmons

nray
31-Oct-2006, 14:32
I have been confusing the angle of view with the angle of coverage. Last week I downloaded the handout "Specs for new Large Format lenses." http://www.largeformatphotography.info/lenses/

This is the source of my confusion. In it, as the focal length increases the angle of view should decrease. But, the numbers for the angle of coverage and image circle vary greatly as the focal length increases. I'm trying to reconcile the angle of view (focal length) with the angle of coverage shown and it does not reconcile. So, in conclusion around a 90mm lens should give me the pleasent angle of view I liked with my old 28mm lens. Correct? Yes.

steve simmons
31-Oct-2006, 14:35
About as close as you can get given the different proportions of the film sizes. If you look at page 30 it should be clear what angle of view and angle of coverage is.

steve

GPS
31-Oct-2006, 14:37
Here is what I said in an earlier post

"Angle of view is a function of the focal length of the lens and the size of the film."


steve simmons

The big truth in its beauty...

nray
31-Oct-2006, 15:09
Yes, that's what I'm after....the truth.

Thanks guys! I think I got it.

robc
31-Oct-2006, 16:06
one of your next questions is likely to be: How much shift should I have available in a lens?

40 to 50mm of shift is a lot on 4x5 format. The XL 110 has way more than that. So much more that it will infact cover 5x7 film with some shift available.
A lens with only 10mm to 30mm of shift will be fine for most landscape work but you may run out of shift for the occasional shot. 0 to 20mm shift will limit what you can do with a lens and is not very suitable for architectural work where you require the use of a lot of shift for tall buildings but it would still be fine for most landscape work.

Ron Marshall
31-Oct-2006, 17:43
The angle of view is determined only by the focal length of the lens, simple geometry only.

Not true. The angle of view for any given lens is determined by the size of the film. A 150mm lens on a 4x5 will have an angle of view of X. That same lens on a 5x7 will have an angle of view of X+ becasue the film is larger and takes in more, in this case, of the image circle.


steve simmons

I wanted to keep it simple for this guy since he seemed to be having enought problems as it was. I should have included, on the same format.

Leonard Evens
1-Nov-2006, 08:49
There was lots of good advice above, but I find some of the arithmetic weird. Let me emphasize that while subjective factors play a role, there are some clear numerical starting points.

Since 35 mm (24 x 36 mm) and 4 x 5 (about 96 x 120 mm) have different aspect ratios, you have a choice of three multipliers. They are

Long dimension: 120/36 = 3 1/3 ~ 3.3

Diagonal: 154/43 ~ 3.55

Short dimension: 96/24 = 4.

For the 4 x 5 equivalent of 28 mm in 35 mm, these give roughly 90 mm, 100 mm, and 110 mm. Note that all of these are greater than what a 3 x multiplier would give, although the long dimension comparison comes closest.

I believe the 3 X multiplier comes from comparing what are considered "normal" lenses for the two formats, 50 mm for 35 mm and 150 mm for 4 x 5. But the diagonal of the 35 mm frame is actually about 43 mm, not 50 mm, so using the latter as the normal focal length is, I think, a matter of historical accident. Usually one takes the diagonal of the format as the normal focal length because that supposedly best approximates what the visual system encompasses when looking at a scene. For various reasons, the 50 mm focal length was seen to work better for general 35 mm photography, although it is a bit long. One is of course free to do the same thing with 4 x 5 by using a longer than normal lens. But then, 150 mm would not be your "normal" 4 x 5 focal length. In converting you should want to preserve the angle of view as measured by one of the three dimensions dicussed above, so a multiplier in the range 3.3 to 4 is most appropriate.

Thalmees
1-Nov-2006, 09:22
Hi nray,
Let me give you one example from the reality. Hope it will work.
Using the formula: AOV = 2X AntiTAN(L/2F) @ Infinity, where:

AOV: Angle Of View,
X: Multiply,
L: Length Of Format(Diagonal, Horizontal or Vertical, which direction you would like to calculate AOV for),
F: Focal Length.
Sure you need calculator: http://www.calculator.com/calcs/calc_sci.html
And reviewing specifications(AOV & Focal Length mainly) of Sinar Sinaron S 150mm f/5.6 from here: http://www.sinar.ch/file_uploads/bibliothek/k_92_Brochures/286_0_prka_objekt_e.pdf (page 5).
As well as knowing the dimensions of the actual printable area of my 4X5 films, has the following dimensions:

Length = 116 mm,
Width = 92 mm &
Diagonal = 148 mm.
BTW: The actual printable dimensions are, some times, little smaller(depends on where film clips was fixed during development). The actual 4X5 sheet dimensions are: 125X99X159.4 mm(L/W/D).

________________________________________________________________________
Now, we can gooooooo. I'll solve the dilemma for the Sinar Sinaron S 150mm f/5.6, leaving the lenses you wish to own for your calculations.
From Sinar catalog, Sinar Sinaron S 150mm f/5.6 has an angle of view(AOV) of 72 & covering power of 214mm(CP: is the diameter of projected image on the film standard or focal plane/Image circle). So, its 72 for a format with a diagonal dimension of 214mm. But your printable area of 4X5 film, can only cover a circle of 148mm diameter. Even the whole sheet of 4X5 film, can only cover a circle of 159.4mm diameter. See the attached photo please(Only part of 72 will be viewed on your 4X5 film & even narrower angle will be viewed on the printable area of 4X5 film).
Applying the equation on the printable area of 4X5 film, will result in a near exact corrected AOV, when you print or scan your film later. My calculations(depends on dimensions given above) are as follow:

Sinar Sinaron S 150mm f/5.6
Diagonal Angle Of View = 52.53
Horizontal Angle Of View = 42.28
Vertical Angle Of View = 34.10
This lens, is equivalent to a lens of focal length of 44mm in 135mm format(if you consider Diagonal Angle Of View); and to a lens of focal length of 46mm in 135mm format(if you consider Horizontal Angle Of View). Remember that 135mm format, has horizontal proportion bigger than the horizontal proportion of 4X5 format.
At the same time, the printable area of my Medium Format, is 54X54mm. So, the Sinar Sinaron S 150mm f/5.6 is equivalent to a 70mm 6X6 lens(if I consider Horizontal Angle Of View).


________________________________________________________________________
I hope this will help.
Good Luck.

Brian Ellis
2-Nov-2006, 16:39
It may help if you just forget the term "angle of coverage" and instead just think of "image circle" since both terms refer to the same thing . In totally unscientific terms "angle of view" refers to what you can see when you look through the lens using a viewfinder on a roll film camera or the ground glass on a large format camera. Image circle is, as its name implies, the circle created when light shines through the lens. On roll film cameras the image circle is no bigger than the diagonal of the film since the lens is fixed in position relative to the film. On large format cameras the image circle is usually larger than the diagonal of the film because using front movements, especially rise, fall, and shift, changes the position of the lens relative to the film and so the circle needs to be larger than just the diagonal of the film.

Two lenses of the same focal length used on the same size film will give the same angle of view (i.e. what you see when you look through the viewfinder or the ground glass will be the same with both lenses). But the size of the image circle may be different because the lenses might be designed differently.

I haven't used scientifically correct terms in all cases here and there are exceptions to some of it but I think it's sufficiently accurate for purposes of understanding the difference between the two terms that are confusing you.

Donald Miller
2-Nov-2006, 17:44
Not true. The angle of view for any given lens is determined by the size of the film. A 150mm lens on a 4x5 will have an angle of view of X. That same lens on a 5x7 will have an angle of view of X+ becasue the film is larger and takes in more, in this case, of the image circle.


steve simmons

Not true. It is not determined by the film size but rather by the amount of bellows extension at the point of focus.

Dan Fromm
3-Nov-2006, 06:15
Not true. It is not determined by the film size but rather by the amount of bellows extension at the point of focus.I think you're mistaken. Please explain further.

Leonard Evens
3-Nov-2006, 06:38
Not true. It is not determined by the film size but rather by the amount of bellows extension at the point of focus.


I think you're mistaken. Please explain further.

The angle of view of a frame of a given size is determined both by the frame size and by the distance of the frame from the lens. For most photography, one focuses on a relatively distant point, and the distance of the frame from the lens is only slightly more than the focal length. Hence, if you use the focal length to calculate the angle of view, the error will be negligible. But for close-up photography, the distance of the frame from the lens can be signficantly greater than the focal length. As a result the angle of view is narrowed. For example, for a normal lens, the angle of view at infinity as measured from the diagonal of the frame is about 53 degrees. For a 1:1 magnification ratio, the distance of the film from the lens will be twice the focal length, and the corresponding angle of view will be about 28 degrees. (In such discussions, the lens is idealized as a point. In actuality, you have to choose some specific reference point such as the rear principal point or the position of the rear exit pupil.)

In contrast, the angle of angle of coverage does not change with bellows extension, at least in principle. (In actuality, the actual optical behavior of the lens may change with bellows extension.) So, the circle of coverage increases in diameter when you focus close-up, thus making more room for rise/fall or shift.

Jim Rhoades
3-Nov-2006, 08:05
Jeez, I know what you guys are talking about and it's still giving me a headache. Nray, Work with your Xenar for awhile before you spend big bucks on another lens. I think you have the Xenar with the 34mm filter size? This is a small light lens, excellent for backpacking. It does not have a lot of coverage. But I think camera movements are a bit overated and over used. Beware that it will throw a good cone of light but there is a fast loss of sharpness in the corners that you might not see on the groundglass. Keep your movements within reason and the lens will be quite sharp. I have one and am always pleased by the results. This is a wonderful lens for landscape, but will not work well with architecture.

Lens snobs don't like the Xenars. Do not be intimidated. Use what you have, use it well, then move on only if needed.