Shallow depth of field lenses for portraiture

[frederick botham]

As I write this I am aware of the many existing questions regarding portrait

lens recommendations but I am looking for something quite specific I feel. You

shall have to excuse my relative inexperience on the subject of large format

(this is my first proper foray into it).

 

I am currently trying to build a 4x5 camera specifically for portraiture. Whilst

it seems that a lot of large format users (correct me if I'm wrong) seek a large

depth of field I am looking to achieve the shallowest I can. Note I do not want

'soft focus'. I would like to do mostly head/shoulders shots and am not bothered

about getting in people's faces, so to speak. Seeing as I am making the camera

myself the length of my bellows shouldn't be a problem, except I have some

bellows already and they aren't tremendously long. Note also I am not interested

in achieving any sorts of movements (I'm not sure this point matters).

 

Now...do you have ANY recommendations? It feels like I might be asking for the

impossible (it's got to that point this evening where it hurts my head to think

about things properly). You can tell me I'm being stupid.

 

Thank you for any input (and if you're interested I'm trying to make a 4x5 TLR.

I'm fed up with not being able to find a Tomiyama Art-Flex anywhere).

[jim_galli4]

Do some searches for portraits done with the 178mm f2.5 Kodak Aerial Ektar lens. I've seen some beautiful extreme shallow results. You might enjoy a wade through <a href="http://tonopahpictures.0catch.com">my site</a> too but I cheat. It's much easier to achieve the ultra shallow dof with 8X10 and there are more goodies lens wise to drool over.

[frederick botham]

Thanks for your reply. From what I've read, it seems like the Ektar lens is likely to be found these days severely browned / yellowed from some sort of radioactive decay from the Thorium elements.

 

I had a brief look through your site. I especially like your photos with the Gundlach #1 4" Petzval. They have a gorgeous quality to them and perhaps something I might be interested in replicating.

 

Thanks.

[frederick botham]

p.s. the photo of the 'work shoes' with the Burke & James AJAX lens is amazing.

[colin carron]

There are two world war II air recon lenses that have big apertures and which are readily available . As above the Kodak Aero-Ektar 178mm f/2.5 and the Dallmeyer Pentac 8 inch f/2.9. Both were designed for use with 5 x 5 cameras with focal plane shutters so you need to provide a shutter.

 

The Aero Ektar (which I have not tried) is the more complex design and I imagine is sharper than the Pentac (which I have tried - acceptably sharp but no great shakes). However the Aero-Ektar usually has a yellow-brown tinge in the mildly radioactive rare earth glasses.

 

The Dallmeyer Pentac is usually unbranded as it was made in quantity for the RAF by a number of makers.

 

Here is a recent thread about these lenses

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00OOhT

[michael_briggs2]

The browning (tea color) of the glass in the Aero-Ektars can be almost entirely cleared with exposure to UV light. I've done it with weeks of exposure using BLB blacklight fluorescent bulbs.

[leonard_evens]

I'm not sure I understand what you are asking for. Large format lenses have relatively little depth of field at the normal distance you would put a subject. A head and shoulders portrait requires a magnification of approximately 1/5.5 for 4 x 5 format. That means the ratio of the subject distance to the focal length of the lens should be about 6.5. I wouldn't want to put the subject closer than about 2 meters (about 6 1/2 feet) from the lens. For that a 300 mm lens would suffice. You would be better off a bit further from the lens, so a 360 mm lens with the subject about 2.3 meters or about 7/12 feet would work pretty well. Using a 178 mm lens, you would have to place the subject at about 3.8 feet, which seems to me to be much too close.

 

In any case, at such subject distances, the depth of field is more or less independent of focal length, depending only on the f-stop, magnification, and maximum acceptable circle of confusion or coc. A reasonable choice for coc for 4 x 5 is 0.1 mm. Both the front and back deptn of field would be roughly equal to the product of the f-number, the coc, and by the reciprocal of the square of the magnification. The last term is 5.5 squared which is 30.25. If you stop down to f/11, the product of the f-number and the coc would be 1.1, and the front and read DOfs would be about 33.275 mm or about 1.3 inches, The total DOf would be about 2.6 inches. Do you really need less DOF than that? If so, you could just open up more. At f/8, it would be 8/11 of the previous number. If you really need less in focus than that, you can try larger formats. For example, for 8 x 10, the magnification would be 1/2.75, but you would use a coc twice as large or 0.2. The net result is that you would reduce the front and rear DOFs at f/11 to 16.4 mm or a bit over 5/8 inch.

[keithostertag]

Jim Galli's site is really amazing, IMHO! Fun and informative! Thanks Jim for sharing!

[david_grenet]

The TLR sounds like a wonderful idea (like a Gowlandflex?) although quite ambitious!

 

As mentioned above, you can achieve very shallow DOF with almost any normal to long lens in 4x5. Using a 300mm lens at f5.6 you will not have the subject's eyes and the tip of their nose in sharp focus! You can try this with a smaller camera and a long lens - at a given working distance the DOF will be the same regardless of format (it'll just be 'cropped').

 

Also, don't forget that if your camera has movements you can select a plane of focus which is not parallel to the camera which may achieve the result you're looking for...

[hitam_jantung]

Frederick, I've been down the very road you're travelling now, and ended up with a beautifully functional 4x5 portrait camera. Mine is made from Spruce, mahogany, Rosewood and ebony and configured as a simple box-in-a-box slider; meaning-no bellows, no movements, no knobs,rails,racks or pinions, no rotating back. The tripod mount is on the front box with the lens, so it's a rear-focus camera, meaning the magnification doesn't change with focus, which is very handy for shallow dof work. There's a fine focus sliding block on the tripod block, but in practice I find it unnecessary. My camera is designed to work with my 91/2" Wollensak Verito at studio distances and removes most camera related distractions. When working in the studio I find I don't even need a dark cloth since my lens is fast and my screen is bright, and stray light is controlled. The camera is very rigid despite its light weight, even with the relatively large and heavy Verito with its huge Betax shutter, and focus locks positively and doesn't drift while adjusting apertures and shutter speeds, or inserting/removing film holders. I don't recommend this design unless you are or intend to hire an artisan of the highest order to build the camera. While the design is simple in concept, it is devilishly complex in detail and requires working tolerances well beyond the reach of a handyman. I built a prototype and it "worked", but so poorly I abandoned the design as unworkable. When a friend visited who is an accomplished luthier, I showed him my failed model and after he stopped laughing, he offered to build a camera based on my drawings and dimensions. I didn't see Saran again for over a year, but when I did, he delivered my camera, and I nearly wept at its beauty and precision. The design and concept were proven; it was just my poor workmanship that missed the mark. My camera and a photo of Khun Saran taken with it are among my most prized possessions.

 

For lesser talents I recommend a tailboard design, which incorporates many of the virtues of my camera but is more easily accomplished.

 

Lens-

 

I find a +/- 9" FL lens ideal for 4x5 portraits, much shorter and working distances become too close, and much longer I feel a lack of roundness in my portraits, which drains too much presence from them, if you'll forgive my indefinite language. I find the Verito a luxuriously versatile lens, capable of a wide variety of interpretations, but any good portrait lens of similar FL should suffice, and you might look for P&S, Heliar, an old Cooke, or one of the modern Rodenstock Imagon, Cooke PS 945, or Fuji SF lenses. In fact, just about any fast 9" lens will probably do, but some are certainly better than others, and much is a matter of taste. Any LF lens shot at apertures wide enough for extremely shallow dof will deliver "soft focus" as much of the image will be out of focus to one degree or another, and it is the quality of the out of focus area that matters most. The Verito and other SF lenses are very capable of sharp images, some by stopping down, others by a dial controlling spherical abherration. A portrait lens is a very personal thing, and one must develop a working relationship with a lens over time to discover its virtues and vices. Happy travels.

[frederick botham]

Thanks everyone for your responses - they are much appreciated.

 

 

Colin: I have been looking at the Pentac lens and thought it seemed like a good option but obviously I would have to find a shutter somewhere.

 

 

Leonard: My thoughts were that any lens would have a relatively tight depth of field but I wasn't sure, so part of my question was seeking to confirm this which you have.

 

I am not sure I know why you suggest that 3.8 feet would be too close to the subject. Do you mean this because so close would produce a sort of 'bubble' head effect of the subject? or another reason perhaps? I am very interested to hear why because I've read quite often people suggesting such distances are way too close. I guess I am just too used to using as close distances as 0.5metres in my 35mm slr. Whilst I'm on that subject, a better way of expressing what I want might be to say that I roughly want to achieve the equivalent of my slr lens' f1.8 but in large format.

 

David: I realise the tlr idea is very optimistic and I am questioning whether to pursue it. At the very least I will still be making a simple view camera. On the subject of movements I am also having second thoughts about saying I wasn't interested including such capabilities. It seems to me now that some limited movements would be very interesting in combination with the depth of field for portraiture (as you suggest). I might have a screw thread running along each corner which attach to the front plate so i can screw in and out (with my hand) each corner of the front plate how I see fit.

 

Hitam: That is a lovely story and you seem extremely fortunate. On a similar note I have a friend who has a small factory nearby that makes metal brackets and similar things and the plan is to use his help in the body construction of the camera.

 

Sorry for my ignorance but do you mind elaborating on what you mean by tailboard design?

 

I couldn't agree more with you when you say it's a very personal thing. In some ways I think this is why I am trying to build my own camera - almost like an extension of this sentiment. Part of the trouble is probably my stubbornness in pumping a great deal of money into this project (I am quite aware that 'cheap' and 'large format' are, in some respects, contradictory). Perhaps I am trying to find that large format doesn't necessarily have to be too dear.

 

Thank you for wishing me the best.

[jim_galli4]

Through the '50's and '60's Burke & James marketed a camera called the Rembrandt. It was supposed to be a throwback to the era of BIG studio cameras I guess but it turned out to miss that mark. It is about the homeliest camera I can think of. That said, you can pick them up on Ebay in fine shape for $100 or less sometimes, and they were designed to have a packard shutter inside. You probably cannot buy the materials to build any thing for what you would pay for a Rembrandt with a nice vinyl bellows. The packard shutter allows you to explore some of the fantastic barrel lenses out there that come along without the need for a shutter. Simply FWIW. I understand that for some of you guys building the camera is 80% of the fun and actually taking pictures with it, well........

[hitam_jantung]

Frederick, I do indeed feel fortunate to know talented and generous people, and to have examples of their fine works. A tailboard camera is a very simple design characterized by a rigid front standard fixed to the bed at a 90 degree angle, and a moving rear standard for focussing. The rear standard might or might not incorporate swing and tilt movements, but rarely shift, or rise/fall. The advantages of a tailboard camera include a large lensboard to accomodate large portrait lenses and their even larger shutters, a very rigid front as a consequence of the fixed joinery of front and bed, and rear focus, which is more important on larger formats where close working distances with long lenses can mean very long bellows extensions. To summarize, the main advantages are: rigidity, simplicity, a large lensboard, and rear focus. Tailboards can be quite compact when designed with a folding bed, and lightweight, but not technically self-casing, although the option of leaving the lens attached during transport can be convenient, and equipping the camera with a simple lens protector is easily done. Finding a tailboard camera in the 4x5 format might be difficult, which is a good reason to build one. If I might offer some advice, I would suggest you don't commit a lot of time, expense, or complexity to your focus mechanism. A well made dovetail slide with a positive lock is more than adequate to the task, and ergonomics is more important than a precision threaded or geared focus mechanism. Portraiture often entails working quickly and intuitively, and the less you have to fiddle with knobs and levers the better. Camera movements are a matter of personal style, but they do complicate camera design, construction and use. For my camera I decided against movements of any kind, and haven't missed them, but my decision was based on years of experience using cameras with movements, so I knew what it would mean for me to be without them. One final suggestion; if you're going to the trouble to design and build your own camera, make it uniquely personal, to fit your hands as well as your vision. It doesn't make any sense to me to build a copy of something you could probably buy cheaper. I admire your spirit and wish you the very best.<div></div>

[leonard_evens]

Why the subject should not be too close in portraiture.

 

The human visual system has a property called size constancy. That means that, within certain bounds, the apparent size of an object doesn't depend on how close to you it is. Ao, if you look at a person's face at 1 meter, 2 meters, and 3 meters, it looks more or less the same. The image produced by a camera doesn't so compensate. It will be much larger for an image closer to the lens. Another related property of vision is that relative dimensions appear to be preserved. When a face is two or three feet from the lens, the distance from the tip of the nose to the ears is a much larger percent of the total distance than if the subject is six to eight feet from the lens. The camera faithfully records this, but your visual system distorts it so you see the same thing. As a result, the faithful camera image looks distorted relative to what the eye/brain sees. When the face is too close, the nose may be exaggerated. As you move the subject further away, you "flatten" the camera image so it better approximates what you see in your mind's eye.

 

This is sometimes called perspective distortion, but that is a slightly different, albeit related, phenomenon. If you put your eye at the same distance proportionately to the print as the lens was to the subject, the image on your retina produced by the print should be the same as that produced by the scene. (But, seeing involves scanning and processing the retinal image, so, as noted above, the retinal image is not what you see.) If you make an 8 x 10 print using a 250 mm lens with 4 x 5 film---so using a 2 X enlargement---, you should in principle view the print from 500 mm, but you would normally view it closer to 250 mm. This won't make a significant difference in what you "see". But, if you use a 90 mm lens, the print should be viewed at 180 mm, which you are highly unlikely to do, and "distortions" at normal print viewing distances should be obvious.

 

Because of considerations like this, you are usually advised to put the subject at some distance to the lens. Just how far the subject should be is a matter of taste. If you like the results when the subject is relatively close, that is fine, but as I said, I prefer having the subject further away, and I believe most people prefer images produced that way.

 

The usual rule of thumb is that the appropriate focal length should be from 1.5 to 2 X the normal focal length for the format. But that is misleading, since it really depends on the format. As I noted previously, if you want to make a head and shoulders portrait, that determines the magnification, once you know the format size. You then have to adjust the focal length and subject distance to get that magnification. If you make the focal length smaller, you will have to place the subject closer to the lens. So you have to decide in advance how far the subject should be from the lens, and then choose the focal length to produce the desired magnification at that distance. I described in some detail above how to do that.

[frederick botham]

Thanks a lot, you have confirmed my suspicions. I think I have found a lens I want and if i acquire it I will be working from there.

[profhlynnjones]

You need a lens of 9 1/2", 10", 12", or 14" with as wide an aperture as possible.

 

Among my LF lenses I still use a WWII era lens for this purpose, a 240mm (9 1/2") Wollensak Velostigmat (Classical 3 element Cooke triplet type).

 

Lynn