I had promised everyone the next video would be a return to medium format. It is not. My Bronica S2A is in pieces on the workbench, mid-way through a focusing screen replacement that has not gone the way I expected, and the camera will not be ready for a few more weeks. (I covered the full saga in the next video on the channel, if you want to know how that ended up.)
In the meantime I have a new lens for the 4x5. A hefty Nikkor SW 90mm f/4.5 that arrived from eBay with some cleaning scratches on the front element and a price tag that reflected those scratches. I have been wanting a wide lens for 4x5 for months. This one was finally affordable.
This is the writeup of the morning I took it out to St Arilda’s Church at Oldbury-on-Severn and used it to test something I had been reading about for months but had never actually done. Camera movements. Specifically, using front and rear standard movements to straighten the converging verticals on a building photographed from below. This is the textbook large-format use case. Every introduction to view cameras talks about it. I had finally got the kit to try it for myself.
The short version is that it works and the technique is more intuitive than the textbooks make it sound, although architecture is still not my thing. The lesson stuck and I have used these movements in shoots since.
The new lens
The Nikkor SW 90mm f/4.5 is a wide-angle large format lens from Nikon’s SW (Super Wide) series. On 4x5 film, a 90mm focal length is genuinely wide, equivalent to around 28mm on a 35mm camera. The “equivalent” calculation is rough because the aspect ratios of 4x5 and 35mm are different (4x5 is 4:5, 35mm is 2:3) but as a rule of thumb, multiply the 4x5 focal length by about 0.3 to get the 35mm equivalent. So 90mm × 0.3 = 27mm. Most people round this to 28mm.
The Nikkor SW 90mm f/4.5 is the brighter version of two 90mm SW lenses Nikon made (the other is the f/8). The f/4.5 is heavier and more expensive when bought used, but the brighter aperture makes a meaningful difference when you are focusing on a ground glass in low light or with a dark cloth over your head. The image circle covers 5x7 with movements, which on 4x5 means you have plenty of room to swing and tilt the lens without running out of usable image circle. The lens sits in a Copal No.0 shutter, which is the standard small shutter for large format wide lenses.
Mine has cleaning scratches on the front element. Cleaning scratches are the tiny scratches you sometimes see on a lens where someone has wiped grit across the glass with a dry cloth. They look alarming under a torch. In practice they have almost no effect on the image because the front element is so far in front of the film plane that the scratches are heavily out of focus. The seller had priced the lens accordingly. I paid roughly two thirds of what a clean copy would have cost. No regrets so far.
The lens is so heavy. About 600 grams, which is more than my Toyo’s lens board is really designed for at the rear of an extended bellows. I will need to be more careful with my setup discipline when using this lens.
Why 90mm is the wide end of “easy” on 4x5
A short technical aside that is worth knowing if you are getting into large format.
Lenses for 4x5 below about 90mm tend to require additional kit to use to their potential. The reason is geometric. A 90mm lens, focused at infinity, needs the rear element to sit about 90mm from the film plane. The Toyo 45C and most other 4x5 monorail and field cameras can compress their bellows to about that distance with a flat lens board. Below 90mm (75mm, 65mm, even shorter), the required distance gets smaller than the compressed bellows will allow. The bellows physically cannot squeeze close enough.
The fixes for shorter lenses are all annoying. You can buy a recessed lens board that physically pushes the lens body backwards into the camera, giving you the missing few millimetres at the cost of finger room and an expensive purchase. Or a bag bellows that replaces the standard accordion bellows with a soft fabric pouch that compresses much further, at the cost of an additional purchase and the faff of swapping it in and out. Or, if you have a field camera, a drop bed that drops the front of the bed down so the lens is no longer obstructed. Different kind of faff.
If you stick to 90mm or longer, you avoid all of this. A 90mm gives you about 28mm equivalent, which is wide enough for most landscape and architectural work. Going to 75mm gets you about 24mm equivalent, which is super wide but starts to require the kit above. Going to 65mm gets you about 21mm equivalent and you are now in specialist territory.
For most people getting into 4x5, the 90mm is the right wide lens. It is what every introduction to large format recommends. I should have bought one twelve months earlier and saved myself a lot of “I wish I had something wider” moments.
At St Arilda’s
I drove out to St Arilda’s Church at Oldbury-on-Severn one cold December morning. This is the third video I have shot at St Arilda’s now (the church has featured on both the Canon AE-1 Program review in colour by day and the 4x5 night shoot in black and white) and the third time I have been pleased that the church has photogenic stonework and dramatic position on its little hilltop.
The church gave me the perfect subject for testing vertical correction. A tall stone building with strong vertical lines, standing on its own with nothing competing for attention, with enough space around it to back up and frame properly. I set up the Toyo 45C with the new Nikkor SW 90mm and pointed the camera up at the church to fit the spire in frame.
The bellows had to be compressed almost to the minimum to focus the 90mm at the distance I was working at. The front standard was about as close to the rear standard as it could physically get. This left less room for movements than I would have liked. I had to be conservative with the rise, tilt and swing settings because the bellows were already at their natural compression limit.
I loaded two sheets of Fomapan 100 and two sheets of Kodak Portra 160 for the colour version. Foma 100 is the cheap-and-cheerful entry-level B&W large format film (£1 to £2 a sheet depending on supplier). Portra 160 in 4x5 was about £5 a sheet at the time. I had budgeted for one or two colour frames at the church and the rest in B&W.
The technique: why verticals converge and how to fix them
Here is the actual technique, which is worth explaining properly because the textbooks tend to make it sound more complicated than it is.
When you point any camera up at a tall subject (a building, a tree, a church spire), the vertical lines in the subject converge towards the top of the frame. This is called keystone distortion, after the keystone shape it produces from rectangular subjects. The cause is geometric: when the camera (or specifically the film plane) is tilted away from parallel with the subject, the parts of the subject closer to the camera are rendered larger than the parts further from the camera. A church spire that is at the top of the building is further from the lens than the church base. The top renders smaller than the bottom. The verticals converge.
The fix on a 35mm or medium format SLR is to either (a) accept the keystone, or (b) point the camera level at the building, frame so the top is just in shot, and crop the unwanted ground out later. There is no third option. You cannot un-keystone an image in-camera on a fixed-back camera. (You can fix it in post-processing, but at the cost of resolution and with some image stretching that never looks quite right.)
The fix on a large format camera is to use camera movements. Specifically, you can move the back standard (which holds the film) independently of the front standard (which holds the lens). The principle is super simple: keep the film plane parallel to the subject, regardless of where the lens is pointing. If the film plane is parallel to the building, the verticals on the building stay parallel on the film. There is no keystone because there is no geometric reason for one.
In practice, getting the film plane parallel to the building can be done in two ways.
The first is to keep the camera completely level (no upward tilt at all) and use front rise to shift the lens upwards. This moves the field of view upward in the image circle. The top of the building appears in frame and the film plane stays vertical (parallel to the building), so the verticals stay straight. This is the cleanest method when it works.
The limitation is the lens’s image circle. As you raise the front standard, you are using more and more of the edge of the image circle. Eventually you run off the edge and the corners of the frame go dark (vignetting). Wide-angle lenses tend to have larger image circles than longer lenses (relative to the focal length), but every lens has a limit.
The second method, used when front rise is not enough, is to tilt the camera upwards as a whole, then tilt the back standard forward (the top of the rear standard moves towards the subject) until the back standard is once again parallel to the building. The film plane is back to vertical even though the camera body is tilted. You may also need to apply forward tilt to the front standard (Scheimpflug) to keep the lens’s focal plane aligned correctly with the now-tilted system. And usually a bit of front rise as well, to fine-tune the framing.
This sounds complicated written out. In practice you make small adjustments while looking at the ground glass and watching the verticals straighten on the screen. The eye does most of the work. The brain follows.
What I actually did
At St Arilda’s I went with the second method because the church was tall enough that front rise alone would have run me out of image circle. The setup was:
- Camera body tilted up by maybe 10 to 15 degrees to include the spire
- Rear standard tilted forward to bring the back parallel to the church
- Front standard tilted forward (a smaller amount) to maintain Scheimpflug
- A small amount of front rise to fine-tune the framing
The ground glass showed the verticals straightening as I made the adjustments. By the time the back standard was visibly parallel to the church (which I checked by holding a small spirit level against it) the verticals on the ground glass were actually vertical. The composition was now what I wanted. I metered, set the aperture to f/50 or so (which is between f/45 and f/64 on the Copal shutter), cocked the shutter, pulled the dark slide and fired.
For comparison, I also shot one frame without any movements. Just the camera tilted up at the church, no rear standard tilt, no front standard tilt. This was the control frame. The verticals would converge dramatically.
I shot a Portra 160 colour frame of the same scene with the movements still applied, because the church is so photogenic in colour and I had brought the sheets along.
The last two frames were a longer-exposure detail of some foreground I cannot now remember in much detail, shot at f/64 for about six seconds. The reciprocity correction was minimal at that exposure length.
The results
The comparison between the with-movements and without-movements frames was as dramatic as the textbooks said it would be.
The without-movements frame has the church looming up the frame with the verticals converging hard towards the spire. The spire ends up taking maybe a third of the width of the top of the frame. The building looks unstable, as if it might fall away from the camera. This is the look you get from any handheld camera pointed at a tall building.
The with-movements frame has the church standing upright in the frame. The verticals are actually vertical. The spire is the same width as the top of the building. The building looks the way it actually looks when you stand at the bottom and look up: tall, stable, photographed truthfully.
The Portra 160 colour frame works too. The combination of muted Portra palette with the stone walls and the grey sky gives a lovely atmospheric church frame that is the kind of thing you might see on the cover of a book about British rural architecture. I am surprisingly happy with it.
What I learned
A few things.
Movements are easier than they sound. The geometry of vertical correction can be explained on paper but the actual doing of it is just “look at the ground glass and adjust until the verticals look straight”. I had been intimidated by the language in the textbooks. The technique took about ten minutes to internalise once I actually tried it.
The new lens is the right lens. 90mm on 4x5 is definitely wide enough for architectural work and has plenty of image circle to give me the movements I need. It stays sharp across the frame even with the movements applied. The cleaning scratches have made no visible difference to the image. Worth being patient with eBay listings if you want one of these.
Architecture is not my thing. I have suspected this for a while. This shoot confirmed it. The church looks lovely on the negative. I do not get the same satisfaction from a properly-shot architectural frame that I get from a well-shot portrait. I am going to keep using these movements for the occasional landscape that has architectural elements in it, but I will not be shooting buildings as a primary subject.
The Bronica S2A is being missed. Twelve frames of FP4 in the Bronica would have been my preferred way to spend this morning. The S2A is back in service now (the focusing screen saga concluded with the original screen reinstalled on fresh foam, as I covered in that next video) and I will be back to medium format imminently.
Next time
The Bronica is fixed. The next outing on the channel will be the writeup of the focusing screen saga, and after that I will get the S2A back out for some actual portrait work. Architecture experiments aside, what I actually want to do is photograph people.
If you have a 4x5 camera and you have never tried camera movements, find a tall building and have a go. The technique will click in about ten minutes and you will fully understand for the first time what large format cameras are actually for. There is a reason architects and product photographers were the last holdouts of large format photography long after everyone else had moved on. The movements give you control that no other format can match.
I will be using mine again, probably not for buildings, but for the occasional bit of focus-plane manipulation when I am photographing people in scenes with deep foregrounds or unusual depth requirements. That is its own writeup, for another day.