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Tuesday, September 27, 2011

Thoughts on Technical Cameras

Today's post is a bit different from other posts I have made...where I typically show one or more photographs I have taken, and perhaps comment on how I made the photograph. I know the watch photographs are very popular, but from your emails, I also know the landscapes and cityscapes have their following. And some of you are also very keen on my views of equipment...the recent and still on-going episodes on Large Format Printing is getting good reception, as were the Focus Stacking articles and those on the Hasselblad H system and Panasonic Micro Four Thirds system.

Today I am going to put down in words my thoughts on this topic of technical cameras.

First, what are technical cameras? Well, they are cameras which offer movements in either the sensor plane or the lens plane.

Second, what are movements and why do we need them? When we speak of movements in reference to technical cameras, we are taking the sense that is applied to view cameras. Ansel Adams, the maha-guru of all photographers has written an entire book on them...see The Camera by Ansel Adams, where he describes the movements of a view camera and the effects those movements have on the photograph. But here, suffice to say, we are interested in shifts - left and right movements of the standards (as the planes of the sensors and lenses are called in view camera parlance), up and down movements. And swings and tilts. These movements can be applied singly or together to one or both standards. Of particular importance to the macro photographer is the tilt movement, where depth of field can be increased by tilting the lens standard while keeping the sensor vertical. This utilizes the Scheimpflug principle.

I already have a very high resolution digital system, the H3D-39, though quite old by digital standards, still produces excellent, large prints. And for applications like macro and landscapes, I don't actually need the features of the newer H4D system: namely the remarkable True Focus system, which is a boon for portrait photographers, and higher ISOs. I typically shoot at ISO 50 or 100, or sometimes 200. I have done some street photography with the H3D at ISO800, and if exposed properly, I find it remarkably grain free, and totally usable.

So why consider another? Well, for the following reason:

1. I want to experiment with movements.

I find for landscapes, and especially some of the work I have done on Travel Photography in the Cityscapes section of this blog. And photographs of the Frauenkirche and Hofkirche which appeared in my book A. Lange & Sohne: The Pour le Merite Collection, with the 28mm, I can capture all of the building without having to tilt the camera up. (see here for a web friendly photograph of this)For architecture, we don't want to move the sensor plane from vertical (or from being parallel to the subject plain) because this will cause the verticals on the building to converge. This may have pleasant effects, but for accurate portrayal of architecture, we want the sides of the building to remain vertical. To do this, we need to keep the sensor plane parallel to the sides of the building. And though the 28mm has enough coverage to still capture the entire building, I end up with a photograph which has a lot of foreground. For the book, the Frauenkirche and Hofkirche photographs work, because I put some text in the foreground, this is the nature of editorial photography. But if I would like the whole church to take up the entire frame and print big, I needed some way to un-converge the verticals. This can be done either in Photoshop, or better, optically at point of capture with a fall of the rear standard, or rise of the front standard.

Also to avail myself to flat stitching, where instead of turning the camera on the lens' nodal point to create a panorama, up to a 3 panel stitch can be made by moving the back and not touching the lens. This produces a superior stitched image, as the panels are from the unmoved lens. With a lens which has sufficient coverage, multi row panels may be created for a very large, super high resolution photograph.

For macros, for example a dial lying on the table. Even at the limits of diffraction at say f/22, it is not possible to render the entire dial in focus. Focus stacking is a method which can go round this, and in many respects better, especially for movement photographs, where the plane of focus is not flat, but also have to follow the height of the movement components. But focus stacking, especially for large prints are very demanding on technique and a good consistent light source...which almost always means I have to have access to a studio flash. This is not always practical, though I do travel with my Profoto Compact 600 setup, which is very good for this application, I sometimes find myself wanting the extended depth of field without having access to a big, heavy studio flash. Also tilting the front standard is the classical solution to moving the plane of focus so that it coincides with the subject, rendering flat subjects like dials totally in focus at a large aperture.

2. Access to the newest lenses, which resolve to 80 line pairs per inch. These are principally made by Schneider and Rodenstock in their digital series of lenses. And are remarkably well corrected, with large image circles which are needed when movements are applied. These overcome the limitations of the Medium Format lenses in terms of chromatic abberation, ultimate resolution. Though the HC lenses are corrected in Phocus, I am a firm believer that if we fix the problems as close to the source as is possible, the better and more elegant the solution.

So who are the candidates? I think they are made by the following:

1. Alpa, of particular interest is the TC and STC.
2. Arca Swiss with the RM2d or RM3d.
3. Cambo with their WRS and WDS1000.
4. Linhof in particular the Techno and possibly the M679cs.
5. Sinar with the Artech.

My views of these cameras are still being formed, and I will cover them in another post later. I will also explain why I am not considering traditional view cameras like the Horseman LE/LX, the Sinar P2/P3, and the like as the base cameras, but why there might be a sort of hybrid solution which might work.

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