AF on wide pirmes

<p>Dear friends,</p>

<p>Since the introduction of full format on DSLR's I have the feeling - particularly for Nikon users due to the compatibility of the bodies with old manual lenses - something is beginning to change in the mentality of many photographers.</p>

<p>I have always felt wide angle AF zooms, whatever their intrinsic qualities, were somewhat incongruous., at least when covering a wider FOV than the one a 35mm is able to offer.</p>

<p>Zooms - either manual or AF - are generally unable to offer a continous indication of DOF along their range, at least unless they are not of the much maligned "pump" type (remembrance of the Nikon 43-86mm one for example which had a DOF abaque engraved on the barrel).</p>

<p>As the lens FOV broaden and the focal length decreases, the number of paces, forward or backward, to frame a subject precisely decreases too. On very, super or ultra wides, it is - most of the time - not difficult to obtain the required FOV by using your feet instead of zooming and the wider the lens, the smaller is the effort.</p>

<p>Wide lenses are producing an inherent DOF which is borader and broader as the focal length shorten. Even a 28mm has an inherent DOF which is very important since the first few larger apertures and you really need a very fast one, used very near to the main subject to perceive a very neat out of focus effect. Moreover (but this is subjective) I think the resultant "bokeh" is never really pleasant, whatever the lens, as the transition between the in focus main subject and the background is too progressive to make the main subject "pop out" as with a tele-lens (or even a fast 50mm wide open).</p>

<p>Taking a picture of a subject very near from the frontal lens of a wide angle generally ends up in a somewhat caricatural rendition. This, once again, limits the practical advantage of using the wide apertures as a mean to isolate the main subject in wide angle photography.</p>

<p>AF lenses, even primes, have a very limited DOF scale on the barrel and a relatively imprecise one due to the necessity to limit the angular movement of the focusing system for a faster AF</p>

<p>Most of the time a truly wide lens is used for its particular perspective rendition and maximizing the DOF properties of the lens by closing the aperture.</p>

<p>From these elements, I have concluded :</p>

<p>AF is more a liability on wides under 35mm as a good scale focusing on a complete DOF scale on a MF lens having a focusing ring with a much wider angular movements form minimum focusing distance to infinity is more useful and even faster and more precise than any AF system</p>

<p>Modern wide angle AF zooms, though they allow for a more limited number of lenses to be carried, are very cumbersome and heavy to carry on a body and their frontal lens is generally very exposed. The weight and volume of two or three wides in the bag being in the end less an hindrance to the photographer's movements and their weight is not much heavier than the one of the wide zoom.</p>

<p>For years, I have been frustrated by the multiplication of zooms and AF lens applied to everything, including the sheer non-sense of AF fisheyes !</p>

<p>It seems the trend in beginning to reverse as more modern manual prime wide lenses are appearing these days, either from Zeiss or, more recently, from Cosina - Voigtländer (20mm f/3.5).</p>

<p>Do you think Nikon should revive a range of manual wide primes (under 35mm) with a moderate aperture (f/3.5 - f/4) covering FX format and affordable, but optically as good as technically possible from the maximum aperture on ?</p>

<p>François P. WEILL</p>

<p> </p>

<p>I dont. 3.5 and 4 are way too slow. id like to see a whole range of 1.8 primes. 1.4 is too expensive and 2.8 a little slow for my liking.<br>

I dont really care about MF vs AF. In my book they have different uses but i tend to agree with you that AF is less useful at shorter focal legths.<br>

All i ask is that we dont get any more "G" lenses. About the only thing I agree with Ken Rockwell upon is that G stands for gelded. If cost is that much of a factor to eliminate a small plastic ring which probably adds 3-4cents onto the cost of each unit, then we need to find a better way to market lenses. I think Nikon has done such a great job of keeping all of thier lenses compatible with all of the cameras, that it would be sad to see that go with all G lenses.</p>

<p>What are you talking about with some lenses having more DOF than others? All lenses have the same DOF. It's pure physics. As for DOF scales, I see them as important in the past but not now. Same for focusing scales. My camera has a DOF preview that I often use, and to fine tune it I simply check the LCD after a test shot. I really don't want to go back to the inconvience of single focal lenses, unless they are special purpose such as tilt/shift. Nikon's latest crop of zooms gives better quality, fast speed, and I don't miss shots because I had the wrong lens on. I don't see any way Nikon would make money on single focal lenses with f3.5 etc. Maybe 40 years ago they did, but technology has passed them by.<br>

Kent in SD</p>

<p>Ken :</p>

<p>What are you talking about when you say all lenses have the same DOF ?</p>

<p>How do you explain a 28mm (i.e.) set at the same distance and using the same aperture has more DOF than a 50mm (i.e.) ?</p>

<p>Of course be it an AF and a zoom or a manual prime at the same subject distance and with the same aperture they will have the same DOF, but this was not the point I discussed.</p>

<p>I just pointed out short focal lens with their intrinsic increased DOF are certainly not is the same need of AF than say a very fast 50mm or a long tele lens. Moreover whane you know how to use the DOF scale on the lens barrel. A procedure I consider the most efficient to focus such wides.</p>

<p>Nobody forces you to " <em> to go back to the inconvience of single focal lenses"</em> if you prefer. I just say this is a mere inconveniency when compared to the (almost) big tele-lens weight and obtrusiveness of modern very wide angle zooms. I prefer to have some weight in my bag than on my camera body, attached to my neck ...</p>

<p>As to miss a shot because you don't have a zoom in a range from 14 to 28mm, most of the time this is purely a subjective impression... Do some trigonometric computations and see how the actual field varies within a few paces with such lenses. Simply, a lot of photographers have simply forgotten they can move too ! ...</p>

<p>As to the DOF preview and an eventual fine tuning with a test shot, sorry to say that but this is laughable in terms of time spent versus scale focusing which can be done even before you point your camera toward the subject... Don't you know what hyperfocal is ? ... Even changing a lens is less time consuming than your fine tuning procedure ! ...</p>

<p>As for the better IQ of modern Nikon wide angle zooms, this is mainly due to the fact Nikon has not yet modernized its prime range... See the results obtained by third party manual focus wides, like the Zeiss ones vs Nikon zooms. Clearly the IQ problem is not with zoom or not or AF or not.</p>

<p>Galen,</p>

<p>I hardly ever used wides wider than 35mm at extreme aperture. Most of the very fast and very wides are not good off the center at wider aperture than f/2.8, most of the time f/4 or f/5.6 give far better results and allow for scale focusing (and photographer's movement effects are really damped by the short focal length anyway) ...</p>

<p>I see no point using a wide from 12 or 14mm to 35mm (not included) at a very wide aperture : as I said, bokeh is never good, unless the subject is very near to the camera, it is almost impossible to isolate it otherwise and if so you obtain a caricature of your subject because of the particular perspective of wide angles... So, unless you picture something almost flat and parallel to the sensor plan (which will enhance the different lens aberrations) under very dim light, I see no practical interest of a very wide aperture on these lenses, moreover when you can get a fine picture at ISO 6400 and closing the aperture a bit.</p>

<p>It seems a lot of pro photographers are re-discovering the virtues of high quality manual wide primes these days through Zeiss lenses and I think Nikon can provide them cheaper at the very limited inconveniency of a somewhat less spectacular nominal wider aperture.</p>

<p>FPW</p>

<p>Well I didn't really get how you arrived to your conclusion from your explanation, but there is indeed a place for primes and a place for zooms, specifically:</p>

<ul>

<li>Primes vs. zooms; if you for example need the 14-24 range, then it is usually most practical to have the 14-24/2.8 zoom. However, if you need only a 20 mm lens, then it's easier to carry just the prime. (I'm skipping quality comparisons as these would be too generalizing anyway). If you need light weight then f2.8 zooms are not the best choice. </li>

<li>Moderate speed; 28/2.8 and 24/2.8 are not large lenses, I see no reason to make slower lenses with modern designs, particularly since focusing in dim light starts to become a pain at smaller apertures than f2.8.</li>

<li>AF vs MF; AF is good when you need to get the shot quickly. AF is sloppiness when you're working on a tripod and the subject isn't moving much at all. Both have their places. I only need the DOF and focus scales when it's so dark that I can't see the subject using live view properly, but at that point they are obviously useful.</li>

</ul>

<p>I agree that in a wide angle autofocus is less often needed than in telephotos, but when I use a wide in event photography, I would prefer autofocus to be available. What are missing from Nikon's lineup are top quality 28mm and 35mm AF-S f/2 prime wide angles. Autofocus lenses can also have an adequate turn of the ring to allow precise manual focus - it's a question of "want" rather than "can" from Nikon's side.</p>

<p>The f/2 maximum aperture is useful in indoor available light photography i.e. weddings. f/3.5-f/4 wide angle lenses are too difficult to focus manually if the subject is moving and the light is dim.</p>

<p>I do find the distance scale and DOF markings on my manual primes to be useful. However I don't see any need for Nikon to make new manual prime designs before they have completed the AF-S prime lineup. There are other manufacturers that supply excellent manual focus primes, but no one except Nikon is likely to make short AF-S primes of very high quality (for the Nikon mount) in the foreseeable future.</p>

<p><em>For years, I have been frustrated by the multiplication of zooms and AF lens applied to everything</em></p>

<p>Well, I can't understand why there are so many 18-xxx zooms either, but apparently that's where the money is. I do like autofocus in a good SWM implementation. The manual lenses I need I already have so now I'm hoping for short Nikkor primes with good center-to-corner image quality and AF-S. I also have no interest in 14-24/2.8 type lenses.</p>

<p>What I find ironic is how people say that zooms allow you to avoid lens changes ... well, you have the 14-24mm on, and you want to go for a close-up of a person. You grab that 70-200 ... quite a hassle, handling these large lenses. Instead you could have swapped that 24 into a 105 which is in your belt pocket. Much smaller objects to swap, at least if they're of moderate maximum apertures. Yes, sometimes a zoom allows you to avoid lens changes and other times it doesn't help at all.</p>

<p>I recommend that you look into the Carl Zeiss and Voigtländer products if you're interested in modern manual wide angle designs.</p>

 

<p>Oskar,</p>

<p>I have to strongly disagree...</p>

 

<ul>

<li>In the 14-24 (or 28) range you don't need a zoom because if you have a 14, a 20 and a 24 or 28 in your bag, changes in terms of FOV will only need a few paces forward or backward and changes in perspective will be determined well in advance of the shooting proper.</li>

<li>Slower lenses are smaller, frontal lens area is smaller too so easier and cheaper to manufacture with extremely high quality and with such primes you hardly need to focus through the focusing screen at usual effective aperture... For example setting my Leica M-mount Voigtländer 21mm f/4 in hyperfocal at f/4 means everything will appear in focus from 2m to infinity. Setting it at the 2m mark will give me a subject apparently in focus from 1.30m to 5m... So what is the purpose of being better able to focus on the ground glass... I agree this is important for lenses with more limited DOF, says from 35mm or 50mm on. But not on very wides.</li>

<li>It is even quicker and far less aleatory (in case the AF refuses to operate properly, something which can happen without much of a warning) to pre-focus your wide by scale focusing as you don't even have to pint your camera on the subject to proceed so. So the AF is not needed and if AF additionally shorten your engraved DOF scale to only the two or three more closed apertures (as it is often the case) AF becomes a liability instead of an help. I agree this is not applicable to longer lenses and from 35mm on I too prefer AF lenses (moreover with my poor eyes!).</li>

</ul>

<p>Modern AF's are great and to a certain extent zooms too when it goes to longer focal lengths. AF will be indeed faster and allows, if well conceived, to focus precisely wide open with fast medium or long lenses even if your eyesight isn't perfect. Zooms can be very efficient and practical when moving to frame the subject implies a somewhat considerable move forward or backward. Something hardly often seen with wide lenses. It is also the indispensable companion of sports photographers who need to be able to frame very fast from a long tele focal length on a detail (or far away from them) and a broader field (or a nearer subject).</p>

<p>As for your last affirmation : >> <em>I only need the DOF and focus scales when it's so dark that I can't see the subject using live view properly, but at that point they are obviously useful. </em> <<</p>

<p>I consider it more than debatable... One of the main control a photographer need to compose his image is DOF and you generally use the aperture DOF increase properties when there is, on the contrary, enough light to close the aperture. The situation you mention is more related to a full aperture use (where you need something more precise than a DOF scale !).</p>

<p>Personaly, I don't want to close blindly the aperture of my wide lens, because it is a zoom without a proper DOF scale, hoping for everything I want in focus to be so, or to rely on a very darken ground glass to look if by chance I can clearly see what is really in focus enough or not, nor I want to have to make a test on the screen moreover whan something fleeting has to be captured.</p>

<p>I don't want to see the wide angle zooms disappear, I just want to have the choice between them and manual primes and for a reasonable price.</p>

<p>FPW</p>

<p>Sometimes you have a situation where you're photographing people and you want a specific person to be pin sharp in the photograph, whereas the rest may be a bit blurrier but it's not as important. There is a difference between a subject being within the depth of field and the subject in the focused plane. And if the subject is moving, in some situations it can be easier to use autofocus. Not in all situations, as it can be very clumsy to switch between autofocus points while things are going on. But there are situations where AF yields superior results more consistently. And if your aperture is f/2 instead of f/5.6, the depth of field is also quite shallow.</p>

<p>Even looking at existing lenses, you <em>do </em> have a choice between high quality manual primes from several manufacturers, and autofocus zooms from Nikon but the autofocus wide angle primes are lacking in image quality at the edges. Do you think that if Nikon made new manual focus prime designs, they would be better or less expensive than what is made by Cosina? I don't believe this to be the case. One lens which I think you should look at is the 24mm PC-E. It's a modern & extremely good design, but the focus scale is not dependable. Infinity is off the mark etc. This is in quite a contrast with the ZF lenses where the markings are very accurate and there are markings for a greater range of apertures.</p>

<p>I think what Kent means is that, for example, any 28mm lens will have the same depth of field at 28mm/f8, regardless of brand name and whether the lens is a 28mm max f2 or 28mm max f4. Once you stop down to f8, any 28mm lens will have the same depth of field. That is indeed a matter of physics.</p>

<p>Kent is not suggesting that a 24mm wide angle and a 17mm wide angle have the "same" depth of field.</p>

<blockquote>

<p><em>All i ask is that we dont get any more "G" lenses. About the only thing I agree with Ken Rockwell upon is that G stands for gelded. If cost is that much of a factor to eliminate a small plastic ring which probably adds 3-4cents onto the cost of each unit, then we need to find a better way to market lenses.</em></p>

</blockquote>

<p>The aperture ring is much more than a 3 or 4 cent plastic ring; there is a mechanism underlying it to move the blades, plus the costs of manufacturing and QA. Since the modern cameras can control the aperture in all modes and the aperture ring must be locked at minimum, it is not useful to most people. I, for one, am happy to see it disappear; I am much happier with the command dials and DOF preview button.<br>

It would be nice to have a mode analogous to the aperture ring, where the DOF preview is on while changing the aperture with the command dial.</p>

<p>It's interesting how different people value the ability to zoom differently for wide, normal and tele. I used to think like Francois here, that zooming is more useful at long FLs because it takes more footwork to frame with a long prime. Then I got a 20-30 and almost immediately made one of my best pics that's still on my wall. However in time the zooms got wider and wider and the range of the 14-24 doesn't suit me. I sold my 20-35 as it would fog inside when I tried to use it in the winter. The 17-35 was out of my reach financially at the time. The 24-70 works well for me now. I guess I just rely on guesswork to estimate depth of field when using the zoom for landscape. I think the attraction to wide zooms is that you can alter the degree of drama and the relative proportions of the subjects quickly by just turning the zoom ring and moving front or back to reframe. Interestingly, I listened to a talk by a young and talented photojournalist this fall and she was using a 16-35, 50, and 85 as her kit. She worked close to the subjects and didn't want a big lens like a telezoom... I guess we can say that individual preferences vary widely. I noticed that Joe McNally now uses just the 14-24, 24-70, 105vr, 70-200, and 200-400... So clearly the modern zooms work well for someone! McNally must have a good back. ;-)</p>

<p>no.</p>

<p>All primes need to be f1.8? Bullony. With the ability of today's DSLR to handle high ISOs, lens speed isn't a big deal if the camera is handled properly. But, that being said any new primes probably will be fast because Nikon is playing to that crowd since those are the folks who are willing to by the latest, greatest even if the lenses (and bodies) they already own do the job. Luddites save a lot of money:)</p>

<p>We can of course disagree, but I will clarify my opinions.<br>

The angle of view and perspective difference is huge between 14 and 24 mm. For those who like to operate mainly in the super wide category (I would prefer the 17-35 or even 17-40 that Canon has) it does make sense to have the ability to quickly switch between these focal lengths if the photographic scene comes up suddenly or if lens changes need to be eliminated.<br>

Moderate wide angles that are f2.8 are not that large. DSLRs are not diminutive anyway, so there is a point of diminshing returns. And life is easier at f2.8 with more light going through the lens. And slower primes atract less market interest.<br>

As for hyperfocal focusing, I feel that this was more appropriate with film. Now we have live view and when editing it's very easy to pixel peep and see if maximum sharpness has been achieved. It leads to higher quality results to determine optimal results on live view than relying on hyperfocal scales, especially since even with with wide angles not everything will be critically sharp due to DOF. The maker of the scale doesn't know anyway what the resolution of the camera is and what the subject is. As for hand held photography, zone focusing can be valuable, but the photographer still needs to know how the lens in question handles DOF and what is acceptably sharp. The transition from sharp to unsharp follows a function, a photo is not suddenly unsharp. In addition, the photographer may at some point want highest possible resolution or settle for 10 lp/mm.<br>

In darkness, I'm using a tripod, so usually I will be able to use apertures such as f5.6 and f8 to have some degree of DOF. When operating hand held, I don't have time to check DOF scales; I know from experience what approximate limits there are for DOF at a given focal length and aperture. For me, this is rarely a problem in practice.<br>

To conclude my viewpoint, my interest in primes is smaller size than a zoom and higher quality. If these are not present then the prime is not very interesting. My interest in manual focus is an accurate manual focus mechanism and the fact that a lot of my photography doesn't need AF.</p>

<p>I believe what Kent meant is the depth of field is the same for all lens when the subject is the same size. The perspective does change. Personally I prefer manual focus when I have the time and I like the DoF scales and I also use DoF preview. Each situation is different and some times AF is very helpful which is why I have some slower AF zooms. I don't think one lens or one type of lens can yet do it all. I am very happy to have many choices but sometimes it hurts the wallet.</p>

<p>Even with the D700, iso 800 is far better than e.g. 3200. With it, my mean aperture is about f/2,8. Any lens slower than that is problematic for me for people shooting and I usully get better results with a lens that is f/2 or faster. For landscape/architecture, f/3,5 is a good compromise for the max aperture; large enough to see through yet the lens can be smaller. But half of my pics are shot in available light, a lot of the time at the limits of my gear so tend to favour fast glass when making purchases. I can certainly see the motivation behind small pancake-like primes but judging from the fact that the 45/2,8 Ai-P is not made any more, the volumes are not large enough for Nikon. Other companies like olympus, pentax and cosina do show them i their catalogs. It seems Nikon doesn't see the value in intermediate aperture high quality, compacy products. They used to, but somehow out of Nikon's favour. Even the pentax lenses are called Limited and a given lens is made for a short while. Same with Cosina Voigtländer.</p>

<p>Carl is correct. DOF is not determined by focal length. It is determined by (1) aperture (2) image size. The wide angle/telephoto "difference" is an optical illusion. This has been well documented: <a href="http://www.bluesky-web.com/dofmyth.htm">http://www.bluesky-web.com/dofmyth.htm</a> So yes, Shun, I am indeed saying that ALL lenses have the same DOF. It's time to put the wide angle myth to bed.<br />Kent in SD</p>

<p>DOF is approximately equal with lenses of different focal lengths <em>assuming constant magnification, </em> but that does not describe a realistic application scenario. <em>In practice </em> you use wider angles to make pictures of several people and teles to isolate on a single subject, for example. Thus the magnification in a typical tele shot is higher. If you take a head shot with a 25mm lens, it'll appear really strange and unnatural, not to mention the discomfort felt by the subject. This is why in many practical shooting situations, you see greater depth of field with wider lenses. Another reason is that when hand-holding, you usually need to use faster shutter speeds with long lenses, which means that wider apertures are needed to get a sharp shot. This further reduces the depth of field.</p>

<p>If you're of the type of photographer who likes to make caricatures of people, and shoot in their face with a superwide, then indeed you need to watch your focus.</p>

<p>One reason to use a wide zoom is that the moderate wide angle can be used most of the time and the photographer can quickly and safely experiment with superwides, without losing the opportunity to get back to the more moderate wide angle with a single twist of the zoom ring. This doesn't really apply for the 14-24 on FX as 24mm is really wide already and not moderate (IMO).</p>

<p>Live view on current FX cameras doesn't allow the whole image area to be zoomed fully into. The center points of the area displayed are all within the DX frame. This basically means that it cannot be used to check edge sharpness. I use the optical viewfinder to set tilt, for example, as I find live view is too limited in the zoomed-in area. With the DX cameras you can, as far as I know, zoom all the way into the corners of the frame, but that's of little comfort to me ;-) But of course, you can use playback with FX and zoom into the shot already taken to verify the sharpness, which I often do.</p>

<p>Unfortunately Kent we are not talking about subjects having the same size on the film. But same distance of focus and same aperture... And here DOF varies considerably from a wide to a tele-lens.</p>

<p>You are just expressing the problem the other way round... At equal degree of magnification (which is in practice not so often the best way to use a wide angle) you're right...But do you use your wide angle lenses for the same subjects and with the same subject magnification in practice? I hope for your models you don't when you shoot a portrait... :)</p>

<p>Illka, I understand your point of view, but, perhaps because of my own style and the subjects I usually tackle I scarcely use a wide angle under 35mm not closed enough as not to use with some profit the DOF scale. Perhaps our final use of shots may differ too : when I operate under the conditions I described earlier it is generally for a publication in offset, scarcely a monumental size of a print. So the better defintion at a reduced ISO setting is not my primary preoccupation, moreover with what a D3 or a D700 can bring at ISO 6400 ! ...</p>

<p>Oskar sorry but the problem with actual DOF capabilities has been evocated before digital photography with the best lenses and most modern films in MF. It was mentioned in the Hasselblad Manual years ago and with a solution : if maximum apparent shaprness is desired under high magnification, then use the DOF scale for one to two apertures more open... This recipe can - I think - be applied to HD digital too.</p>

<p>In a broader perspective DOF might be shallow with a very wide angle at f/2 but you have to forget two points to use this aperture to this goal : The subject must be near to the camera with all the associated perspective inconveniencies and you cannot hope for a high definition at the edges even with the cream of the crop in terms of lens and light fall will be present at the corners.</p>

<p>For me very wides, superwides and ultrawides are mainly landscape with effect or crowd photography lenses where the use of an important DOF is exploited to give a dramatic perspective to the scene. But the very special effect the persopective of such a lens precludes its use as a true portrait lens but if you want to end up with a caricature.</p>

<p>New photographers who never knew the primes as their main equipement can work easily with AF wide angle zooms ? May be. Do they obtain convincng result ? Certainly. Does this habit (and in fact the use of AF in general) transformed the style of many pictures when compared to those taken earlier ? I'm convinced the answer is YES. Both techniques may be valid, but not for the same subjects. I see more and more pictures with (IMHO) an outrageous abuse of wide apertures and far too much areas out of focus. Clearly the camera and lens combination commands, not the photographer in those images. As far as I'm concerned, I prefer a good DOF scale and a total control on the DOF and I ever operated more reliably and faster than any AF (and with more discretion by the way) using hyperfocal and not pointing the camera toward the subject until the very last moment... at least with wide primes.</p>

<p>Now, of course Oskar is right when he says the transition is never immediate between sharp and unsharp areas... To be more specfic the one and only area which is really in focus is the plan on which the lens is focused. The rest just appear sharp to our eyes (circle of confusion). But at the same distance and with the same aperture, a wide angle will have a smoother transition from apprently sharp to unsharp areas than, say, a tele lens like an 85mm. Which means the transition which appears rather neat with a 85mm and detaches the blurred background from the main subject will appear far more indistinct on a wide lens. I don't feel the effect of something still very recognizable but unsharp behind the main subject is really desirable, but I admit I'm very subjective here. I generally use wides when I want to restitute the subject in its context and I use their DOF properties to make this context as sharp as the main subject.</p>

<p>In landscape photography with a small format camera, I still believe - due to the feeble level of restitution of the minuest details when compared to a large format view camera - the best way to make you picture "snap" and capture the attention is to include something of interest (and sharp) in the foreground inscribed in the vastness of the countryside (also sharp) to give an imprssion of depth. But again this is personal.</p>

<p>As for Nikon, I know they will make first what is the most profitable for them. I just hope a certain way to take pictures will surface again and make this kind of lens profitable for them.</p>

<p>FPW</p>

<p><em>The subject must be near to the camera with all the associated perspective inconveniencies and </em></p>

<p>I would put it this way: "The subject can be near to the camera which creates a dynamic perspective and the viewer gets a sense of being involved in the activity, instead of being a faraway observer." :-)</p>

<p><em>you cannot hope for a high definition at the edges even with the cream of the crop in terms of lens and light fall will be present at the corners.</em></p>

<p>The 35/2 ZF is sharp to the corners wide open and few others are sharp in all but the extreme corners (28/2 Ai-S, 24-70/2.8 at 24mm, if you allow for field curvature and somehow focus without recomposing). There is a bit of light falloff but they're ok. The 25 ZF and the 24 PC-E have a lot of falloff wide open. Also, my Mamiya 7 wide angle is the 50/4.5L and that also needs to be stopped down to f/8 to get rid of falloff, but sharpness is very even across the frame and it is distortion free. Some lenses work better for documentary work than others. My favorite for people shots is the 28/2 Ai-S, it gives images with a pleasant character though it's more blue than most lenses, so a WB adjustment may be needed. I don't usually go mindlessly to shoot it wide open without good reason but it has always worked impressively when I have had to do so. I've even had a non-photographer use it and he managed to nail the focus perfectly, wide open, so the lens is clearly worth a high commendation. ;-)</p>

<p>My problem with DOF scales is that they assume that a certain degree of magnification of the final image is sufficient. Also, the scales cannot predict the advance in camera and printing resolution. E.g. a scale might be valid for a 5x7" enlargement with reasonably good print quality. What if you want to go to 11x14"? Then you need the experience to know what aperture is needed or a tool to determine if the image is sufficiently sharp.<br>

It's an old rule to use the DOF scale to focus according to a one step lower DOF scale than the aperture that's used, but modern technology gives us new tools to determine if DOF is sufficient, making the DOF scale less important than before.</p>

<p>@F.P. Weill--<br />It would be just as accurate to say there appears to be more DOF in a photo enlarged only a small amount (4x6) as there is in a photo enlarged greatly (11x14). All lenses do have the same DOF, but the variable to the human eye is the magnifcation.<br />I'll go into a situation that shaped my feelings towards not only DOF, but also the single focal lenses like you are talking about. Ten years ago I found a small area where a herd of deer were caught by a blizzard and died. The skulls were in a tight group. I decided to photo them using my Bronica 645. I had lenses 40mm, 75mm, 150mm, 250mm. I first tried using the 150mm to get three skulls in focus. I couldn't get all three even stopped down to f32. I thought, "Silly me--I should use the 75mm for more DOF." I put the 75mm on and moved in closer to maintain the same framing. I got the same result. So, I went wider and put my 40mm on and again moved in closer, to preserve the same cropping. Again, same result. Then I thought, "I'll put my longest lens on and go for the "compression effect." I mounted the 250mm and backed off so I had the same framing in my viewfinder. And, same result. All of these lenses had the same DOF, aperture for aperture. Exactly the same. DOF is determined by image size (magnification) and aperture. This episode was one of the reasons I ended up going to 4x5. With that system I could simply tilt the lens and get all three skulls in focus. So that's my advice. If someone is looking to max out DOF, buy a tilt/shift lens. The Nikon 24mm PCE is on my list. <br />The focus scales on the Bronica lenses were never precise enough to be a whole lot of use to me, and neither were the ones on the Nikon lenses. The DOF scales were mostly an approximation, and to get exactly what I wanted I always ended up checking the DOF preview button anyway. In winter I mostly photo at night, in darkness. Getting sharp focus with f2.8 or f4 is a problem for me, as is checking DOF. I have solved that by setting a small flashlight pointed towards the camera where I want the focus to be sharp. This works 100% and is precise. I use f2.8 zooms because of the image quality and reduced lens changes in the field. As an outdoor photographer it's not always possible for me to move in or away from my subjects. Thus, a high quality zoom is my choice. I'm thinking that now that technology has shifted so fast, most of us now rely on checking the LCD for focus points than using scales on lenses. If there was a demand for the scales, they would be there. I'm not knocking anyone who prefers the scales at all, I'm just saying that many people are now using a different method and the demand for lens scales seems to be greatly reduced.<br />Kent in SD</p><div></div>

<p>A lot to digest here, that perhaps I will do later. While I agree that autofocus is not required, and even a pain in the neck, for ultrawide angle lenses I don't think Nikon needs to, or would, turn the clock back and produce manual focus lenses again. I have the Nikon 14/2.8 AF and at least they put on a decent depth of field/aperture guide, although I wish it went to the minimum of f22. The rest of my lenses, which I purchased within the last three years, from 28 to 400 are all manual focus. If you desire manual focus lenses there are many choices that are easily available and that will last for many years to come.</p>

<p>The ring zooms don't have DOF markings while the push-pull zooms do. I can't think of any easy way to implement a two-ring zoom with DOF markings - maybe if you can do it, send the suggestion to Nikon. ;-) All my primes have DOF markings next to the distance scale. Clearly Nikon hasn't eliminated them deliberately; only when it can't be done. The 35 DX doesn't have a distance scale so no marks, either, but it is an exception.</p>

<p>I can't think of anything more irritating than the process of changing focus points. When I use a tripod I usually fine tune the focus manually.</p>

<p>John, Nikon just last year introduced and brought three new manual focus lenses to the market. And nice lenses they are, too.</p>

<p>I know Nikon continues to make a few original manual lenses available for sale but the new ones you refer to, are they the perspective control ones? I ask because I think all PC lenses including Canon EF ones can only be made manual focus, so it is not like they chose to release new manual lenses. </p>