Lens Tests

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It's obvious on this forum that people have rather strong opinions about the qualities of various lenses for Leica M cameras. Speaking for myself (and I suspect others), I can't afford nor do I want to buy elaborate lens test equipment for this purpose. Therefore, how do people go about testing lenses that lead to the opinions they have about them? Does anyone follow a systematic routine or procedure to test his/her lens? If so, what do you do and with what film do you do it? Thanks for your suggestions. Dennis

-- Dennis Buss (dbuss@rider.edu), March 22, 2002

Answers

1) Lens test targets taped on a wall of my house, and evenly lit. Camera on tripod, 50X the focal of the lens away from the target.
2) CAREFULLY focus on the center of the target, then shoot 1 frame at each f-stop. Re-focus lens and repeat the above step. You can usually do two lenses per roll in this fashion.
3) I use Velvia, or in a pinch Provia or E100S.
4) I then compare the transparencies under my best loupe, which is a Peak Scientific 16X loupe. I have, however been castigated by members of this group claiming my loupe is not good enough for critical lens tests. It has been further suggested by one member that I need a high-quality microscope to really tell the difference. BUT, the above works for me, and that is all I really care about! Cheers,

-- Jack Flesher (jbflesher@msn.com), March 22, 2002.
Take lots of pictures. Look critically and note the lenses that take the pictures that you like. Most people, even non-Leica enthusiasts, can see a difference with 4X6 color prints. Even people with untrained eyes can usually pick out photos taken with a Leica. The question most asked by those with untrained eyes is, "What film do you use?"

-- Doug Landrum (dflandrum@earthlink.net), March 22, 2002.
testing lenses at home is a very difficult task. jack's protocols sound aout rite, but there are so many sources of error even if you take all the obvious precautions. few walls are really flat, and few are actually completely plumb. even if the wall is "perfect," you need a rather extraordinary set of levels to ensure perfect alignment of the camera. even assuming these obstacles are overcome, there is always a margin of error with focus, no matter how careful you are. and then there are film flatness issues to worry about, as well as exposure (exposure certainly affects sharpness). then, even if you achieve a perfect test, there is a surprisingly large amount of sample to sample to variation among "identical" lenses. in the end, i think it is best to leave resolution testing to those who have a proper test bed (and by the way, many repair shops that do have a lens test set-up will test lenses for a modest fee, producing very detailed data. these are usually aerial measurements which remove lots of the variables. if you must test at home, then i have to agree that the best way is to simply take lots of pics and look very critically at the results. the absolute best photos in the bunch will show you what the ens is capable of, and you can strive to achieve that quality in all of your pics. P.S. everyone keeps talking like m7s are not available in the u.s.a. yet. ken hansen and tamarkin have sold their first batches, and several local dealers where i live have the black .72 version in stock.

-- roger michel (michel@tcn.org), March 22, 2002.
Lens tests mostly hogwash. Best thing is to walk around town and see how you like the lens itself in real performance, not in some lab :D

-- Alfie Wang (leica_phile@hotmail.com), March 22, 2002.
I take pictures, with K64 if I can. If I like how the pictures look I keep the lens, if not I replace it. That's how I ended up with Leica lenses.

-- Douglas Herr (telyt@earthlink.net), March 23, 2002.
All of the above - especially the Alfie method.

I figure I need to know how well the lens will perform (or which of two lenses will perform better) in the actual situations I will be photographing. This is not as rigorous as Jack's (or probably Erwin Puts') procedures, but works for me.

I also test for things other than resolution/MTF/micro-contrast - such as tonal rendition, focusing accuracy with a given body, image color bias, etc.

Since I tend towards documentary/people photography, I go back to places where I will find: lots of people, or certain kinds of light, or a specific range of colors (often modern architecture with it's subtle reds, greens, grays and beiges are great for comparing small differences in color).

And then I just take pictures, for the most part as I normally would. But when comparing two lenses I have to use fairly static subjects so that I can get mostly identical pictures.

When I AM checking resolution - I look for things with fine type or other details. For some reason motorcycles, with all their exposed machinery, or car tires, with fine raised type to compare resolution and contrast at the same time - seem to end up in a lot of my tests.

I don't use tripods, although I tend to use fast shutter speeds since I'm mostly looking at performance wide-open. Since I (almost) never use tripods in my 'real' pictures, differences that can only be seen using a tripod are not that important - to me. (And I hope I make that clear if/when I post an opinion).

And in a sense I'm ALWAYS testing my lenses - by reviewing my pictures and seeing where they work best and where they (or I) fall down on the job.

If I express an opinion here I TRY to show some kind of objective examples - even at 72 dpi you can show some useful stuff by blowing up a piece of the image so that each dpi represents 100 lines per mm (e.g.) As in THIS post from last fall.

Same goes for films: I use my most-commonly-used shooting films (Velvia and Pan F) since I need to know what a given lens will do on those emulsions regarding color or sharpness or tonal range.

-- Andy Piper (apidens@denver.infi.net), March 23, 2002.

After being misled by photographing resolution charts at about 25xfl, I've settled into testing lenses by photographing the same "standard" scene every time I want to check a lens: a white church with dark shingled roof and several trees on one side, in full sunlight at about 45 degrees. I shoot it from a distance that puts the "face" in the center of the image and the trees all the way into a corner, at close to the same distance.

I've become so accustomed to seeing those images in negative form (enlarger and grain magnifier) that I can learn just about everything I need to know about lens performance (except close-up, of course) from a series of these shots from wide open to closed all the way down. Of course it is not quantitative, but it does represent the "hard" problems I tend to throw at lenses with my style of photography: sharp breaks from very bright to very dark areas, fine detail in extreme corners, highlight contrast, shadow contrast. These are done with a fine grain film.

The only other thing I need to do is something like an environmental portrait, a general scenic with cumulus clouds (if possible), and a few out-of-focus images of tree branches (focus ahead of the branches so that they are the background) to see what the bokeh is like. These are done with my general-purpose film for that format (usually TMY). The portrait and scenic give me a sense of... of... errr... the overall "look", whatever that is. Ah, my Leica Summicaron 50/2.

Myron

-- Myron Gochnauer (goch@unb.ca), March 23, 2002.

My procedure for lens test

-- martin tai (martin.tai@capcanada.com), March 23, 2002.
See also thread at photo.net Lens test at home Bob Atkins messages

-- martin tai (martin.tai@capcanada.com), March 23, 2002.
I have no scientific method to test lenses myself. It has been already demonstrated elsewhere more than one time the only scientific way to test a lens performance is to use a FTM bench.

But this scientific method is not ever the right way to appreciate the actual performance of YOUR lens nor to appreciate the real practical utility of the performances of a lens in everyday use.

First, my advice is to take some precautions:

Despite the fact some manufacturers (between them Leica of course) have a very stringent control, you may buy a new lens which has a defect. Even serious manufacturers might have tolerances such as the performances of the lens may vary within limits broad enough from the theoretical ones as to be sensible in current use (it happens to a friend of mine with a Hasselblad lens), beware to the fact a lens within the manufacturer’s tolerances will generally not be refunded or exchanged. Anyway, as soon as possible after buying a new lens, test it and if a defect or abnormally low performances appear bring it back to where you bought it.

Another circumstance which might be frequent with second hand lenses is a defect due to a shock or any other kind of accident. Sometimes, the glues used many years ago with which the lenses were assembled had been altered in time (it seems to be a rather frequent occurrence with some Leica lenses from the 50’s for example). Fungus might have altered the surface treatment and no cleansing procedure will restore its integrity. Dirt might have accumulated inside (though a proper cleansing of the lens by the manufacturer’s authorized service will generally restore the performances, it will be costly). Slight misalignment of one or more group is a very vicious risk as it won’t be detected by a close examination of the lens with bare eye. It is generally the consequence of a long use particularly by a professional photographer who is liable to treat his lenses with much less “tender loving care” than an amateur due to the condition of exercise of its profession. Just have a rule: never buy a second hand lens without the guarantee you can bring it back and be refunded if after a test roll any defect appears.

Second, a lens is generally as good as you consider it for your work.

Objective tests will reveal the objective performances of a lens. All published tests of the new generation of Leica M lenses proves they are better performers than the preceding generations, and most of them are in fact the best game in town.

But sometimes this edge in performance will be lost. Simply because the way the lens is handled in actual life doesn’t permit it to show its superiority. If you read some of Erwin Putts' reviews on Leica lens, you will see he clearly indicates for some of them that only the use of a heavy tripod will reveal the exceptional definition of the lens. So to say, it will hardly be a frequent occurrence in real life as an M body (or any equivalent M mount SFRF for all intent and purpose) is not frequently used that way. In some occasions the splendid qualities of some very fast lens at full aperture will be impossible to use practically. A M body with x 0.58 viewfinder magnification or an Hexar RF with a x 0.6 magnification will be unable to focus properly a f/1 50 mm Noctilux or a f/1.4 75 mm Summilux for lack of sufficient efficient rangefinder base. So you will end up with blurred pics for lack of precise enough focusing. On the economic side, if you don’t currently use maximum aperture, to spend two or even three times more on a lens which is faster than the cheaper alternative will be useless (and might even sometimes lead to poorer pictures as some of them performs well only at wide apertures, their performances being degraded when used with smaller ones). Some non-Leica and much cheaper lens will perform equally well when closed one or two f-stops from their maximum aperture. This seems to be the case of many Voigtländer lenses. They seem to be even better all around performers than pre-aspheric generation equivalent Leica lenses and today Leica lenses have only a real edge wide open or so… My advice is to study carefully reliable published tests and to avoid to be fooled by bench results without perfectly realizing where the edge in performance of the Leica lenses is really apparent and compare these situations with the ones you are likely to encounter in your own work. It is useless to waste money for something you will never see in actual life, better to buy two useful lenses instead. The kind of film you actually use is also a very important data. Many modern high end lenses will only reveal their superiority with very fine grain slow films. Do you really use 25 ISO-ASA film currently in your camera?… With a 100 ISO-ASA slide film or a 400 ISO-ASA B&W film, the superior resolution will sometimes never show.

Now some more subjective impression might influence your choice. There is a frequent debate regarding the qualities of “old” Leica lenses, versus the present versions. Scientifically speaking, the modern ones have the edge (and sometimes by far). But aesthetically speaking, you may prefer the rendition of the old ones for specific applications. For example, a softer lens might be preferred for portraiture, and the famed “bokeh” (which is a very subjective element) of the old lenses might be preferred to the more abrupt transition of the modern ones.

All in all, scientific testing, beyond the reach of many of us for lack of proper equipment, is only a guide to the “raw performances” of a lens while it is the only objective way to judge it. But these results must be interpreted within the boundaries of your actual use and your own taste in the all subjective matters of rendition.

Home testing with a test pattern is useful only to ascertain if a lens has no defect. Though it will reveal abnormal behavior of a lens, so real optical defects, it will never be a sufficient guide to the objective quality of lens which has no evident defects. After passing successfully these test, the performances of a lens must be appreciated in real life if any kind of comparative study is undertaken. “Overkill” will do no harm though but to your bank account… Which is also something to be considered, don’t you think so?

Now, a more personal note:

This is the way I chose a lens and I intend to complete my equipment… Not to be considered as a guide but as an example, because the conclusions are valuable for me and may differ for you.

My limited budget has not permitted me to replace my old M5 which died of an economically irreparable shutter, by an M6 TTL. After pondering the things for a while, between buying another second hand M5 (hard to find and now very costly for such an old model due to the collectors’ renewed interest in this model) and a brand new Konica Hexar RF (for which my dealer has to convince me by letting me test it for sometimes) I finally went for the Hexar RF.

I realized very quickly the limitations imposed by the lesser magnification of its viewfinder in terms of very fast wide aperture lenses use from 50 mm and up. Fortunately I had no such lens in my bag. This very same limitations forced me to trade my 135mm f/2.8 lens with ears (the ears were not really adapted for the Hexar viewfinder which was partially blacked out) for a band new M Hexanon 90 mm f/2.8 which, after testing, revealed itself a mighty good lens. But I was able to keep my faithful Summicron 35 mm F/2 (Leitz Canada) as an almost standard lens. Soon thereafter I had the opportunity to secure a 135 mm f/4 Tele Elmar of pre-1992 vintage in really mint condition and it works admirably well with the Hexar, even at full aperture (but is more difficult to frame due to the finder magnification of course).

I now intend to expand my lens range as my budget will allow. How will I proceed?

You know now each time I buy a lens, second hand or new, I test it, first with a test pattern, then in real conditions of use. So this procedure will be applied to any lens to come. But I have also to take into account my budget limitations, the limitations implied by my finder magnification and the way I intend to use the lenses to come.

The exceptionally wide angles:

Actually anyone using a Leica mount RF camera has no real choice but to rely on the Voigtländer range, Leica doesn’t produce any such lens.

In the V-länder range you can buy a 12 and a 15 mm lens… Though I would have preferred to go for maximum field and related effect, the price of the 12 mm (be it a bargain for the quality of the lens) is beyond what I can expect to reasonably spend for a lens which after all is a “special effect” one. So I’ll go for the 15 mm which has an enviable reputation and cost approximately half the price of the 12 mm. I was very attracted by this lens until their 21 mm appeared… Now it is no more in the first place of my lens to be bought list.

The very wide angles:

What 21 mm ?

Here is a typical dilemma between genuine Leica lenses and a third party lens.

The choice is between the present Leica 21mm F/2.8 aspheric lens, The older 21 mm f/3.4, the oldest 21 mm f/4 and the new Voigtländer aspheric Color Skopar F/4.

The new Leica lens is obviously beyond the reach of my poor budget. Both older versions are rather expensive second hand acquisitions and when I see their tests by Erwin Putts, it doesn’t seem they are exceptional in any way by modern standards. As the V-länder lens is considered by Putts a better lens than the both, my choice is obvious, I’ll go for the third party offer. But should I have been able to afford the modern Leica lens, would it have been my choice? The answer is no. Few real life situations will require the use of a 21 mm lens wide open (where the Leica is definitely superior to the V-länder offer, both in maximum aperture and in performances wide open). As the V-länder lens is perfect at f/5.6 which perfectly suits my requirements for such a lens (I hardly use very slow film in my camera) the Leica lens would have been an overkill. Moreover the compactness of the V-länder lens cries for it to be present full time in the bag, the same do not apply to the rather cumbersome Leica lens (not to speak of its value when it goes to the eventuality of damage or steal risks). Definitely a case lower theoretical performances are not a liability in actual photographic situations. And, remember, the price of a Leica accessory finder is almost the one of the lens and its accessory finder as marketed by Voigtländer! …

I’m found of wide angles, and this one is the first lens I will buy.

On the contrary, I’m not very attracted by the 24 mm focal length… This is a personal bias as I find this kind of wide angle to much a compromise between wide and very wide angles: Not the special feel of a real very wide, nor the capability to use it without too much apparent perspective effect with a careful aiming angle. But should the need arise, the only valuable choice will be the Leica offer. Even if the Voigtländer 25 mm is considered by many a good lens, and will generally be easy to use with its DOF focusing ring, at wide aperture and with a subject quite close to the camera, I feel much more comfortable with a rangefinder coupled lens. The problem will be for me to afford the Leica lens and its accessory finder… And as it is a kind of lens I don’t feel necessary, I doubt I’ll ever make the effort to buy it… It is in the last place in my list and in the “optional” column…

Wide angles

The 28 mm is another typical dilemma. The best one is obviously the splendid aspheric 28 mm f/2 from Leica… A very expensive lens which by the way buries its competitors chiefly at wide apertures. I like the 28 mm wide angles because they have already a very extended depth of field but can be managed to minimize the typical wide angle perspective. They are very handy when you have no distance enough to capture a subject and still don’t want the wide angle use to be apparent. As their limited focal length is favourable to hand held use even at relatively slow speed (moreover with a rangefinder camera) and (again) I hardly use very slow films as everyday workhorses, I don’t see the maximum aperture performances so critical. The other serious offer is again from Voigtländer as the Konica lens doesn’t seem to be on the same league in optical performance. Here we have a f/1.9 lens (so “officially” even more open than the Leica one) which is also an aspheric one. Reading the test of it by Erwin Putts, It is clear that it is not a serious contender wide open to the Leica offer. But, though it is still a less performing lens than the Leica lens, the edge of the last is so small that it won’t show in most situation. As the V-länder lens is considered superior to any previously produced Leica lens and the present f/2.8 model, it is clear it will be my choice, for economic reason but also because its performances suit my requirements.

35 mm, I have already a Summicron F/2 lens, but it is an old one of pre-aspheric generation. Though I’m satisfied with it, I will eventually trade it one day for its modern aspheric brother which is absolutely superior and the best 35 mm available for general purpose. Why to spend such an amount of money? Just because 35 mm is for me almost the standard lens for a range finder camera mainly used for candid shots. Here wide open use is something very frequent and I don’t want to compromise but now my budget doesn’t allow another solution. Though I don’t want to buy the Summilux version which appears to be less efficient when its aperture is closed and I also use my 35 mm DOF scale when required and I don’t want to lower its performances in such situations. Third parties lenses are not even as good as is my present older Summicron so they are dismissed right away.

The “normal” lens

I’m not a 50 mm “aficionado” May be because I’m myopic and used to a slightly “wide angle” kind of natural vision through my glasses. But I acknowledge the advantage of having a lens with a very natural perspective even when having to isolate somewhat a subject without negating totally the influence of its environment. Moreover, when used with a wide aperture, this lens has just enough of DOF to separate clearly the different plans and still be easy to use as to keep the main subject perfectly in focus. As it is a lens which is bound to be used frequently (though I don’t consider it THE standard as a lot of photographers do, at least for an RF camera), I don’t want to compromise. Ideally the Noctilux would have been my choice, but beside the fact it is a very expensive choice, my Hexar RF body is unable to focus it properly wide open, so one of its particular quality will be lost. The Summilux F/1.4 is not a very efficient lens as it loses its qualities fast when the aperture is closed. So it goes for the universally acknowledged Summicron f/2… A lens which is not a very expensive one and has still the same optical formula as the older ones… So a second hand choice might be seriously considered. I don’t see any need to go for a third party offer there as they are generally inferior in practical use and not really economical when compared to a good second hand Leica lens. The f/2 aperture will be sufficient for me considering the kind of films I generally use for a hand held operation.

The 75 mm lens

Not really a tele-lens and very specific to RF cameras, the 75 mm has a special place in my “expansion plan”. I intend to use it outdoor about the same way I intend to use the 50 mm indoor. It will permit me to capture in a more intimate way a subject without isolating it from its environment. Though I will be able to record it from a tad more remote place and with a real ability to focus it fast. As a mainly “outdoor” lens, I don’t need a very wide aperture to operate it most of the time, besides, the Leica offer, the magnificent Summilux f/1.4, will not focus properly wide open with my Hexar RF (nor with a 0.58 Leica M either by the way). As for the 21 mm, the Leica offer is also a cumbersome and heavy device. Its price is of course at the high end. On the contrary the moderately open (f/2.5) Voigtländer offer is a very compact design which is easily kept in the bag at all times and a very performing device from the tests I read with a much more affordable price. Very seductive indeed and it is the second on my list of most wanted lens.

Tele-lens

The 90 mm variety is something very classical as a portraiture lens for a 35 mm RF camera. Not as cumbersome and difficult to frame accurately as a 135 mm one. For economic reason, I was forced to resort on an M Hexanon lens, the only Konica made one I happen to have. Do I regret it ? Not at all… I’ve tested the 50 and 28 mm from Konica and read a lot of tests on their 35 mm. For me the only lens Konica currently produces (I don’t know about the special series of wider open lenses issued with special kits of Hexar RF) worthy of attention when comparing the price to the performances is the 90 mm f/2.8… My opinion is the value for money of the other M-Hexanon lenses is relatively poor (particularly when you consider what could be available second hand in genuine Leica lens range or new in the V- länder lens range). But the 90 mm performs well enough. Only the 90mm f/2 from Leica will be a real improvement above it and the price of it as a new is much higher. Though the 2.8 aperture is somewhat limiting the low light capabilities of the lens, no one should ignore the fact that a x 0.6 magnification finder is not the best for accurately focusing and moreover framing in low light, low contrast situations a 90 mm lens. I’d really want Konica to issue something akin the new Leica accessory magnifier to help there (which, by the way will permit to reconsider the case of very wide aperture lens). But even wide open this lens performs good enough with the kind of film I use of course… I won’t change it for the Leica offer unless I can improve the finder with an accessory magnifier.

135 mm … Though I do appreciate the very real qualities of my Tele- Elmar f/4 135 mm lens, and I know my faithful f/2.8 135mm with accessory “ears” was probably not as good a performer and more cumbersome to use, we are now reaching the very limits of a rangefinder camera in terms of ability to frame perfectly a lens. True the “ears” of the f/2.8 were cumbersome but they immensely helped there. I’m still able to focus perfectly and frame appropriately my Tele-Elmar with my x 0.6 viewfinder but this is not a 100% success attempt. A sufficient reason to be satisfied with the Tele-Elmar and not to go for the newer apo f/3.4 which will be probably only a better performer with an appropriate M x 0.85 or M x 0.72 model with the magnifier.

Would I like to have some no more or yet not produced lens ?

Sure enough… A 50 or 65 mm close up lens with appropriate “ears” would be welcome to tackle macro-photography at small magnification ration (x ½ for example) as not to be obliged to carry my medium format SLR with me should I need to get a close up. I also dream of a 180 – 200 mm fast tele-lens with correcting and magnifying “ears” to reach some subjects. I know the result will be somewhat cumbersome, but surely less than to have to carry two different systems at the same time…

Here is the depiction of my way to chose and the reason why… You may have different requirements, but I think the method is here.

Friendly

François P. WEILL

-- François P. WEILL (frpawe@wanadoo.fr), March 23, 2002.

When I get a "new" lens, first I make sure the mechanical parts are functioning smoothly and properly. Then I shoot a quick roll of bulk-loaded b&w, making sure to examine precise focus at wide apertures and several distances. I'll also try to shoot some photos similar to what the lens will typically be used for. Then I develop and examine the negatives carefully to check focus and to make sure there isn't something horribly wrong.

Beyond that, I do my "tests" by taking photos, and I form opinions about the lens based on how well I like the results it can produce.

-- Mike Dixon (mike@mikedixonphotography.com), March 23, 2002.

A very interesting discussion of lens selection François. I just recently acquired a 0.58 M6 (to compliment my 0.85) and have started some tests with my 75mm Lux and 90mm Elmarit-M. My first series was to determine focusing accuracy and depth of field characteristics. I shot obliquely (20 degrees+-) at 1.25 meters onto a table top with newsprint using the SF-20 flash, tripod, cable release and Velvia. I was surprised to find that my focusing accuracy at 1.4 was very similar between the 0.58 and 0.85 bodies (of course this was on a tripod and I took my time). I also did some outdoor shots at 1.4 in our dreary Washington State weather and again the focusing accuracy with the 0.58 M6 was excellent. Maybe it was because I just got new glasses, my eyes were fresh, or beginners luck ;-), but the 75 Lux is working well on the 0.58. In reviewing Erwin's rangefinder accuracy tables (pg. 228) the 75 Lux/0.58 Combo should be up to the test at 1.4 with a 0.03 blur circle but does not meet the more demanding 0.02 blur circle test unless stopped down to approximately f/2.0. BTW, at 1.25 meters the 90 Elmarit-M is the superior lens in contrast and resolution at the common apertures I tested (2.8, 4.0, 5.6).

-- Doug from Tumwater (dbaker9128@aol.com), March 23, 2002.
Looking back over this post, I should have clarified that prior to owning Leica lenses, I never bothered to test them in the fashion I described above. It was when I got into Leica, and began to read about all of the strengths and weaknesses of the various versions of the same lenses, that I got curious about the lens' real performance charachteristics... That, and I felt I had to prove to myself the darn things were really worth all the money as I was paying for them!

But in the end, I think the last two sentences of Douglas Herr's three sentence post sum this issue up the best... (Appologies to Francois, as I admit I did not read all he published here.)

:-),

-- Jack Flesher (jbflesher@msn.com), March 23, 2002.

I would have to say that on this group (and any other group) the best lens tester I've seen so far is Mike Dixon. Instead of some weird, boring, stupid, Air Force test target, he uses these really outrageous chicks. I think the Mike Dixon Standard should become the new lens testing standard. I also think the Top Lens should be the one that gets a chick to disrobe. (The 90mm Elmarit-M seemed to leave her cold, but as soon as I bayoneted the 75mm Summilus-M into place, she began to unbutton her blouse.) So who's with me on this?

-- Glenn Travis (leicaddict@hotmail.com), March 23, 2002.
"Outrageous chick" tests only tell you what the lens looks likes taking "outrageous chicks", unfortunately, so is only of some value to those of us who take pictures of other things as well.

-- Robin Smith (smith_robin@hotmail.com), March 25, 2002.
I read this thread earlier. Did anyone mention using a flash when testing lenses? It would freeze any motion and up the contrast, especially of newsprint.

-- chris chen (chrischen@msn.com), March 25, 2002.
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