4x5 - 90mm lens for general architectural work - what minimum image circle?

The subject line sums it up really. Basically I've been struggling on

with a 150mm lens for architectural work, but now want something a

little wider. This is the first LF lens I'll have bought, the 150

came second hand with the camera. 90mm or shorter seems to be the way

to go, but the spec sheets are making my head hurt - is there a

general rule of thumb that I can use to select a minimum image circle

size for architecture? Yes, I know it depends heavily on the subject

matter, so just a finger in the air estimate. While we're on the

subject, I guess I should also invest in a bag bellows, recessed

board and short monorail. Given the apparent fragility of the bag, is

this something that I should be buying new?

Depending on the camera, you should OK with a 90 on conventional bellows. Having said that I'm spoiled with an Ebony which has a small bag like extension to the front of the bellows as standard, so they don't get sticky when you crank the front standard up.

 

Architecture is potentially the use for which you'll need as much coverage as you can get to avoid vignetting when using extreme front rise to keep your verticals nice. The Super Angulon 90 XL would be a good choice from this point of view, but it is a large lens and has a 95mm filter size, which doesn't suit everybody. The super symmar 110 XL is highly thought of too and has large coverage. i'm saving my pennies for one right now!

Being the diagional of the format size is what's necessary to just cover, 162.6395563mm (*S*) image circle is the minumin with NO movements for 4 x 5. I don't think a bag bellows is necessary for most 4 x 5 cameras. A bag bellows limited movements on my Sinar F1 with a 90mm Super Angalon. What camera are you using? Recessed boards often impair access to shutter controls and prevent use of shutter release cables.

Ideally, you would want to be able to put the bottom of the building at the bottom of the image. This is equivalent to shifting the lens upwards until the lens axis coincides with the top of the film area - regardless of focal length!

 

A rough calculation, well rounded off gives: 80mm (half film diagonal)+ 60mm (half film height, "portrait" orientation) x 2, or 280mm.

 

Round this down a bit more for practical use, say 260mm due to the angle between rise and diagonal...

 

So an image circle of 260mm is sufficient for just about everything, anything less means you won't be able to get only the building in the image without using lens tilt as well. Note that 260mm is not the minimum, it's the optimum. Anything more is overkill, anything less can still be used. You don't need a 110mm Super-Symmar XL, but it might be nice. A Super Angulon 90mm/f:5.6 XL with an image circle of 259mm might be the optimum...

 

With anything around 90mm with this size of imace circle, light falloff could necessitate a center filter. I would also recommend a bag bellows, we're talking of 6cm rise here - at most.

4x5 (which is actually 95x120mm) requires 153mm of image circle to cover without movements, 224mm for "full" rise in landscape, 258mm for "full" rise in portrait (where I define "full" rise the rise that will put the horizon at the bottom of the frame). As was suggested, Schneider's Super-Angulon XL 90/5.6 would just cover that. A Super-Symmar XL 110/5.6 would give you some margin in case you need extra movements.

 

Getting so much rise with a short lens may be mechanically tricky. I have to use a bag bellows on my Sinar F with a 150mm as soon as I use non-trivial amounts of rise, and I am very far from using a "full" rise.

I have used a 90 mm f8 Nikkor-SW for exterior architectural photography and never felt that I needed more coverage. Nikon specs this lens for 105 degrees / 235 mm diameter of coverage. With 4x5 film, this allows a front rise of about 47 mm in portrait orientation and 53 mm in landscape. I'm not saying this is the best 90 or that it will handle all situations, only stating my experience versus the specs.

 

Calculating the desirable coverage as being able to place the optical axis of the lens on the edge of the negative is probably excessive. This would allow you to level the camera and shift the bottom of the building from the middle of the negative to the edge of the negative. While one typically uses front rise to eliminate some of the foreground while preserving parallel vertical lines, eliminating all of the foreground will rarely look good -- one will typically want some context for the building.

 

My opinion is that the 90 mm Super-Angulon XL is probably has more coverage than most 4x5 photographers need. If you want to have the most coverage possible to cover the rare extreme use, then it's the lens to have. It would also be ideal for 5x7. If cost or size/weight are considerations, then another 90 mm model will probably be satisfactory for the vast majority of photo situations.

 

Whether you need a bag bellows, recessed board and short monorail depends on your camera. Most cameras can cope with a 90 mm on a flat board. Probably most cameras would do a better job with a bag bellows. You can figure this out without having a lens by positioning the lensboard about 90 mm in front of the ground glass. Now try raising the front standard 40 or 50 mm. If you can position easily position the lensboard at this distance and apply the front rise without overly straining the bellows, then your camera is OK as is. If not, then you need either a recessed board or a bag bellows. A recessed board can cause difficulties accessing the shutter controls, while it takes time to exchange a regular bellows for a bag bellows. Unless you expect to be in a hurry, the bag bellows is probably easier.

 

If you can buy a used bellows with the right to return it after inspection, I don't see why not. Inspect it for wear and test it outdoors in sunlight. With the lens closed and the dark slide out, move the camera around for a couple of minutes so that the sunlight strikes the bellows from many directions. If negative film develops clear, then the bellows is most likely fine. Another technique is to use a flashlight in a dark room to search for pinholes.

The Nikon 90mm f8 is ideal. It has plenty of coverage and even though an f8 lens I find viewing the screen okay!

I shoot of lot of exterior and some interior architecture with a Sinar F2. For 19 years I used a Grandagon 90mm f/4.5 lens with a bag bellows. The bag bellows is excellent for lenses up to 150mm and often even for 210mm. The bag bellows on this camera easily allows for full front standard rise. The lens was a limiting factor. At maximum front rise, which you need for tall building too close to you (a frequent situation) the Grandagon runs out of image circle and vignettes at the top (of image) corners. I recently purchased a mint Schnedider 90mm XL on Ebay and with its greater image circle I no longer have that problem. So in architecture bag bellows are a must and image circle is everything. It would be worthwhile to also look at the Schneider 72mm XL.

David Kaufman

A 4 x 5 frame is about 95 x 120 mm. If you were to shift all the way upward (60 mm) in portrait mode, so the lens axis were at the bottom of the frame, you would need a radius of sqrt((95/2)^2 + 120^2) = 129 mm, or doubling that, a diameter of about 260 mm for coverage. You would certainly need a bag bellows if you found a lens with that coverage, but, being right on the edge, it seems questionable whether you could get decent results, even if the camera allowed such extreme shifts. Of course, it is the image circle that counts, and no fiddling with movements, such as tilting the camera, will change that if you want to avoid converging verticals. Also, you may need a center filter with large shifts.

 

It should also be noted that extreme shifts of that size, particularly with a wide angle lens, will produce noticeable "perspective distortions". These are not true distortions in the mathematical sense, but result from looking at a part of the field one can't see without shifting one's view. An example is three dimensional spherical shapes becoming ellipsoidal.

 

Probably you can make do with a shift significantly less than a full 60 mm upward. A lens with only a 235 mm image circle or even less might do.

 

In practice, I think it better to choose one's position so that extreme shifts are not required, but then the problem becomes that there is too much foreground included in the frame. If the foreground is empty, that can be a problem, but a creative use of the near/far principle can enhance the result if one includes something of interest in the foreground.

 

I've been managing with a 90 mm Rodenstock Grandagon N f/6.8 lens with only a 221 mm diameter image circle. But my camera, a Toho FC-45X has a fixed bellows and shifts are limited when the standards are that close. At times I wish I had a 75 mm lens, to which I would add Toho's version of a bag bellow, an eccentric lensboard. That would help me in situations when I can't get far enough back, but would still not deal with the foreground issue.

Thanks for all of the answers folks - very useful. I ordered a wide angle kit for my camera new, after looking through the auction sites it just seemed easier, and I want to get out and take some photos not wait for months for a bellows to come up. Not very expensive either, given that I paid next to nothing for the camera. Lenses are far more plentiful, so I'll be bidding and seeing how I get on, and buying new is way too expensive! Looking forwards to trying my 150mm lens with bag bellows too, as I've wanted to compress my regular bellows just a fraction more on a number of occasions.

Just to round this off, I got a 90 mm f8 Nikkor-SW from my friendly, neighbourhood web auction. Should arrive in a couple of days - can't wait!