Selecting large format lenses appropriate for your cameraAug 26 '04 (Updated Oct 12 '04) Write an essay on this topic.
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The Bottom Line Large format is very simple once you step back and forget everything you know about 35mm photography. It ain't an SLR!!! so don't treat it like one.
If ever there was a branch of photography that was steeped in "voodoo" and folklore it would be large format photography. At first the lingo might seem confusing. I'm sure that anyone reading this review who is not involved in large format photography might think this review seems steeped in technical jargon. But the nature of the format requires the use of technical terms that are not normally needed in medium and small format photography. A basic understanding of the large format camera is needed to fully utilize the information below, but its the kind of knowlege that 30 minutes of web searching could provide if you took the time. So if concepts like "image circle", "camera movements", and "bellows extension" seem like rocket science then you will need to familiarize yourself with these ideas before selecting any lens, or camera for that matter. I would also add that no amount of reading or questioning can replace the actual experience of using the gear. When in doubt, try it out and let your gut make the decision for you. Your gut is normally right. In theory, all large format lenses can mount on all large format cameras so long as the lens can physically fit on the front standard. Since large format cameras come in so many different styles and purposes, there are definitely times when a lens might be innappropriate for a certain camera depsite its ability to physically mount on the lensboard. Large format photography has been around for over 160 years, and its peak is long past.As a result there is a huge array of quality used gear on the market today. If you have the cash and prefer new gear then some of the info below will not apply, but much of it will. The main purpose of this review is to provide a "checklist" that will help the first time or novice large format photographer select a lens kit for his/her camera without wasting money or effort on unsuitable gear. When selecting a lens for your large format camera you need to take into account several things.... 1. Will the lens cover the format you are shooting? Most LF lenses will cover 4x5 formats but there are a few 2x3 cameras still made and those lenses might not work well with a 4x5. Those shooting formats larger than 4x5 will have to be especially careful of lens coverage since larger cameras had far fewer lenses made for them. A 4x5 camera ( by far the most common LF format) requires a 160mm coverage circle to shoot without vignetting. That figure is without any movements at all. Most 4x5 shooters are in luck. So long as the lens was not designed for a 2x3 camera (somewhat rare) then most LF lenses will technically work for 4x5. Larger format shooters like 5x7 and 8x10 photogs will need to be extra careful here. 2. Will the coverage of the lens allow for the movements that you routinely use? Be realistic here....don't throw out a lens because it has a 210mm circle just because you MIGHT need more coverage. Do you NEED it or not? Hopefully you are an accomplished photographer enough that you know your needs. Your camera might even dictate your needs. If you have a field camera or press camera then the amount of movements that your camera can make might limit the image circle needed. Of course, most monorail cameras are only limited by the bellows for their movements. I used to think I needed massive coverage because I wanted to do all these huge manipulations of the image plane. Well it ends up that I am routinely satisfied with minute movements...and I rarely do anything drastic for the kind of photography that I prefer. As a GENERAL guideline... most landscape work and general nature photography rarely involves massive movements....the same goes for portraiture. Some architectural shots ( particularly wide angle interior shots) and product photography needs more movements than normally used by the landscaper. As a suggestion I would say that the more you use your camera inside, the more likely you need larger movements. As a general rule I would suggest that if you are into no movements ( like with most portrait work) then a 160mm circle is fine for 4x5, medium movements you should look for up to about 210-240mm and that should cover most shots. I find most field/technical and press cameras work well in this range. If you need massive movements (like with a studio-based monorail design) then you might need 280mm or more image circle. Also remember that wider-angle lenses focus at much shorter bellows extensions and as such, their useful image circles are often smaller than for longer lenses because the possible movements are limited by the camera. The ironic thing is that movements are almost unlimited for longer lenses, but are rarely needed....and wider lenses usually need more movements but are often limited by the camera and bellows. 3. Does your camera have enough bellows to use the lens? Sure, you can fit it on your camera, but will that 600mm lens actually focus on your camera? As a general rule of thumb you need a bellows extension equivalent to the focal length of the lens to focus at infinity....and more than that to focus closer. The thing with LF photography is that a lens can ALWAYS focus closer so long as you have enough bellows. At twice the focal length of the lens ( in bellows extension) you achieve a 1:1 reproduction ratio. The kind that makes most 35mm macro shooters drool. Technically you can keep going and get closer but bellows extension, light fall-off and serious DOF considerations limit this to reasonable magnifications. Most cameras can accommodate a 300mm lens focused at infinity, but you might need significantly more bellows to focus that 300mm lens for a portrait in a tight studio. So don't make the assumption that just because you have "X" amount of bellows that you can accommodate "X" focal length lens. That might make for a costly mistake. I find most 300mm bellows cameras should stick with 270mm or even 240mm lenses as their maximum focal length without using tricks like funky lens boards to make up for the bellows. So I guess what I'm saying here is that if you have a press camera or field camera you are probably looking at 300mm as your top end lens simply due to bellows length. That is the equivalent of a 100mm lens in 35mm terms.....a short telephoto portrait lens. 4. Does your camera have the ability to focus that WIDE lens that you want? On the other end of the spectrum is the problem of short bellows draws. A wide-angle lens might only need 75mm or 90mm to focus. The stiff construction of most accordion bellows serious limits the abilities of many cameras to use these lenses. Even cameras that can mount them and focus them often cannot use movements with them. Bag bellows are a solution but do you have one? Can you even get one for your camera? Is the extra 10-15mm of width worth the cost and hassle of the bellows. Sometimes recessed lens boards can solve the problem, but sometimes not. Make very sure you know the limits of your camera before investing in that 75mm ( or shorter) lens. Ironically many older monorail cameras are very limited in their ability to focus very wide lenses because the front and rear standards do not come close enough to each other....or the movements are hindered by design limitations and not bellows. 4. Is the lens mounted in a shutter that will fit on your camera? Many smaller cameras cannot accommodate lenses mounted on Copal #3 shutters ( common on long lenses and on lenses with large apertures). Sometimes you can get custom lens boards made but even then, the physical size of the shutter might limit the movements of the camera. This is common on technical cameras with tapered bellows. Monorail cameras rarely suffer from this limitation. Also be aware that there are differences in the types of shutters that are found on large format lenses. Copal, Compur and Seiko and the most common found on current lenses, but there are a staggering array of shutters found on older lenses. Beware of "barrel" lenses unless you fully understand the concept and the trade-offs imposed by such a system. Some cameras can be fitted with electronically controlled shutters and do not need shutters in the lens assembly. Current versions of this system are made by Sinar and Horseman. This is very advanced gear and carries an understandably high price tag. Older mechanical systems, particularly the system found on Graphlex cameras can be great if they are accurate...and nightmares if they are not. One of the great benefits of large format photography is that you can change cameras and still keep the lenses. So if you choose your lenses wisely then you can upgrade relatively painlessly.....if you have barrel lenses then it might be a nightmare experience unless your next camera has the same arrangement. Also, be aware that there are things called "press" shutters that can be self cocking. One press of the cable release cocks and releases the shutter. Some photographers feel the extra effort required to actuate the shutter increases the liklihood that you will jar the camera during the picture taking process. Not a problem with a press camera that is handheld and used with flash.....but it "might" be a problem for the traditional tripod mounted camera that might not be rock solid when tightened down and used for longer exposures in natural light. I don't want to scare anyone away from press shutters, just be aware of the situation and think about it before purchase. In addition, many of these shutters must be held open manually with a cable release in "bulb" mode in order to focus the camera. These lenses were designed to be used on "press" cameras ( obviously) and these were often focused with rangefinder devices as opposed to ground glass. The need for speed dictated the shutter design. These are not bad shutters, but be aware that they impose a slight inconvenience on the user when placed upon a traditional large format camera. 5. Is the lens bright enough to focus under your "normal" operating conditions? That F/12 convertible lens might be cheap but can you focus it in broad daylight even under a dark cloth? In the studio it's a lot easier since you can dim the lights down except for the subject, but it's a real pain to focus a dim lens in daylight even with focus aids. This doesn't make the lens a bad lens, just a hard one to focus. So if you are working outside a lot, or are a little hard of seeing, then that F/5.6 lens might be a better choice. OF course this plays into shutter size as well. You need larger apertures to focus ....mostly for outdoor field cameras, but the shutter size limits the size of the possible aperture....which normally has to be small to physically mount on the camera. Also, larger aperture lenses are much larger and heavier than their small aperture cousins....and since DOF considerations largely prevent an LF camera from being used at such large apertures anyway, aperture is largely a focusing concern and not a shooting concern....at least for those looking to create an image with pictorial realism ( as opposed to painterly or soft-focus effects) 6. If the shutter serviceable? And is its physical condition or specifications good for your application? This is mostly a question of whether you shoot E6 or print film. If you shoot transparency film then you cannot afford to have a shutter that is off by 1 stop. Older shutters are often WAY off and some older shutters were never designed with transparency film in mind. Some older shutters were designed within 1-stop tolerances. Good enough for print film ( I suppose) but totally inaccurate for E6 film....even if the shutter functioned as good as the day it left the factory it would probably not be good enough. Now how does this affect you? Well if you shoot E6 you better get a modern shutter and keep it well serviced. Those who shoot print film can deal with lesser shutters but I think any photographer would prefer accurate shutters for his/her work. Of course, if you always shoot at F/32 with ISO 100 film then maybe you always shoot bulb anyway, so its not an issue. Tungsten studio shooters would find shutter problems to be HUGE! since faster shutter speeds are needed. Flash stuido-shooters should have no problems with inaccurate faster shutter speeds since it won't effect the exposure. 7. Is the lens itself in good condition? Avoid any lens that shows signs of lens separation, fungus or serious marks on the elements. The rear element is more critical than the front when it comes to scratches and nicks. Depending upon your style you might not even care. In her biography, it is said that Margaret Burke-White's first camera had a cracked lens, but since she preferred the "painterly" approach ( which is soft focus) the crack did not cause problems with her images. So some artists might not care at ALL about such things. Small items like interelement dust and hairs are rarely a problem unless they are severe. 8. Is the lens useful for color work? if you are into color photography you might want to avoid lenses made before WW2. They tend to give a pretty poor rendition of color. There are exceptions, but I think that you should be looking for a lens under 50 years old with some coating on it. Coatings ( whether multiple or single) improve light transmittance, often improve color performance and accuracy and reduce flaring. Don't feel that you have to have the latest multicoated wonder. Most single coated lenses made for LF cameras will deliver excellent color reproduction. For black and white work pretty much any anastigmatic lens will deliver favorable results. ( and yes....that is stolen from Ansel Adam's "The Camera"...best book ever written on the subject.) 9. Sharpness... I left this issue for last because it should be the LAST criteria for selecting a lens for your camera. Most modern lenses ( within the last 30 or so years) deliver a level of sharpness that surpasses most photographers' abilities to deliver that sharpness to film. I will keep this argument short. Look on the net for more info. The first people to admit this are normally those who do lens resolution testing... The reasons for this are pretty basic... a. film flatness is a serious issue with LF and only the best vacuum backed holders deliver extreme flatness suitable for high-resolution photography at large apertures. If you use Readyloads then forget it....use F/32 just to overcome the flatness problems with your film holder. b. most films do not resolve as highly as modern lenses. For example, Provia 100...one of the tightest grain transparency films out there, cannot deliver more than 60 lines/mm in real world conditions ( i.e. real world contrast vs. the 100:1 for a test chart). There are exceptions... but they are few and far between....and almost all black and white. Tech Pan comes to mind, but it's being discontinued. c. The need for massive DOF, even with movements intended to increase DOF, requires small apertures, which limit the ability of a lens to resolve at its peak. F/8 or F/11 are great for 35mm or med format, but normally unsuitable for LF. Since many lenses peak at F/11 or so any aperture smaller than F/11 will mostly likely start to suffer from diffraction which can lead to maximum resolution passes of only 40 lines/mm AT BEST!!! d. enlargement size.... if you are still caught up on resolution, then look seriously at your intended enlargement size. As long as you can get 40lines/mm onto film ( not terribly hard).. you can make RAZOR sharp 20x30 inch images. Do you really need bigger? REALLY? On a regular basis? If you shoot LF to make contact prints then pretty much ANY lens that can cover the format can be used to make images sharp enough to hold up to serious scrutiny with a magnifying glass. Need proof? go look at some old photography at a museum.... old contact prints. The lenses were CRAP but the images are spectacular in sharpness. ------------------------------------------------------ conclusions.... basically it's simple. Most lenses made in the last 40-50 years are pretty good candidates for your camera so long as you go thru the above tests to check for suitability with your camera. If you shoot Black and White you have even more options. When in doubt, just remember that all the "masters" used equipment that would be considered garbage by today's standards. I'm sorry but I defy anyone reading this to surpass an Ansel Adams print and I don't care what equipment they use. If Ansel could do all that with "garbage" then what can you do with the "good stuff"?... spend more time doing it and less time agonizing over the quality of your gear. Of course, I wish I could take my own advice. I admit to my own "bullet chasing". Now you will notice that I didn't spend a large amount of time discussing focal length considerations. There are no set rules regarding which focal lengths are BEST. Your specific lens focal length choices should be made from personal experience. First, consider which focal lengths you normally use in 35mm photography. Then eliminate the focal lenghts that are not "practical" for large format photography...this is usually the longer end of the spectrum. It also eliminates most fisheye and extreme wide angle photography although there are some extremely purpose built camera-lens combos that can achieve these results. What you are left with is the wide focal lengths, the normal focal lengths and the "portrait" lengths. I think it makes sense for most people to consider a 2-3-lens system from a wide ( approx 90mm), a normal ( 135mm or 150mm) and a portrait length ( 240-300mm). Many people get by with just a normal. If you have huge bellows then consider a longer lens. Most field and press cameras will be limited to this basic 3-lens kit by design. Personally I do not find it necessary to try and cover the intermediate spectrum between these focal lengths, since often the desired effect can be achieved by merely moving the camera a very short distance to get the desired composition. Don't feel that you have to have an intermediate lens between 90mm and 150mm. In 35mm terms this is merely the difference between a 30mm lens and a 50mm lens. If funds are no object or if you find yourself constantly needing something with a 40mm length, then sure, go ahead and buy one. If your artisitic vision requires an extremely wide lens then there are a few lenses and camera combinations that will help you put that vision on film, but expect to pay big bucks for the privilege.  |
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