stump4545 Posted January 26, 2012 Share #1 Posted January 26, 2012 Advertisement (gone after registration) when shooting wide open when your subject is off center and you focus on your subject and then recompose your shot what technique should i keep in mind to maintain sharp focus? i am thinking just to keep my camera body on the same plane when i recompose because just .5 inch could make a difference at f1.4 at 4 feet. any common mistakes to avoid? tks Quote Link to post Share on other sites More sharing options...
Advertisement Posted January 26, 2012 Posted January 26, 2012 Hi stump4545, Take a look here accurate focus wide open and recomposing. I'm sure you'll find what you were looking for!
jaapv Posted January 27, 2012 Share #2 Posted January 27, 2012 (edited) http://www.l-camera-forum.com/leica-forum/leica-m9-forum/130720-m9-faqs-frequently-asked-questions-answers.html#post1378521 And a number of threads on the subject. Edited January 27, 2012 by jaapv Quote Link to post Share on other sites More sharing options...
zlatkob Posted January 27, 2012 Share #3 Posted January 27, 2012 That is a great question. Ideally you would move backward a little when recomposing. If you were to keep your camera body in the same spot, the focus plane will shift a little behind your subject as you recompose to bring your subject off-center in the frame. This link may be helpful: The Problem With The Focus-Recompose Method Quote Link to post Share on other sites More sharing options...
stump4545 Posted January 27, 2012 Author Share #4 Posted January 27, 2012 wow, thanks for the insight article. moving back a bit after recomposing makes sense. since a lot of leica shooters are shooting at 1.4, .95 etc.. is moving back little after recomposing a common practice just wondering because it makes sense but i never heard about it? seems hard to judge just how much to move back though..might still oof the shot. Quote Link to post Share on other sites More sharing options...
Michael Geschlecht Posted January 27, 2012 Share #5 Posted January 27, 2012 (edited) Hello stump4545, Just remember: When you focus on point "A" & then recompose to point "B": The line of focus is an arc the same distance to you as the center of the eventual composition. Left to right as well as up & down. The image plane you focussed on is not the image plane that you are framing & capturing. After recomposition you are capturing a plane which is further away from & @ an angle to where you originally focussed. Adjust acordingly: The larger the angle of your arc from focussed point to center of composition the more you must compensate. Simple. Best Regards, Michael Edited January 27, 2012 by Michael Geschlecht Quote Link to post Share on other sites More sharing options...
dwbell Posted January 27, 2012 Share #6 Posted January 27, 2012 Bit "out there" but why can't the focus patch be bigger? 2 Quote Link to post Share on other sites More sharing options...
Erik Gunst Lund Posted January 27, 2012 Share #7 Posted January 27, 2012 Advertisement (gone after registration) That is a great question. Ideally you would move backward a little when recomposing. If you were to keep your camera body in the same spot, the focus plane will shift a little behind your subject as you recompose to bring your subject off-center in the frame. This link may be helpful: The Problem With The Focus-Recompose Method Are all Leica M lenses flat field lenses? Quote Link to post Share on other sites More sharing options...
zlatkob Posted January 27, 2012 Share #8 Posted January 27, 2012 seems hard to judge just how much to move back though..might still oof the shot. Ha, you're right, it is hard to judge as you're shooting. In the link above, the writer states that if the subject is 4 ft. from the camera, and the distance from point A to point B is 2 feet, then the offset 6 inches, so you would have to move back 6 inches when recomposing. If his calculations are correct (I calculate 5.666 inches), then you have an approximate 6-inch "rule of thumb" for those distances — but that only applies to those specific distances. The depth of field at f/1.4 and 4 feet is much less than that, so the difference between moving back vs. not moving back should be visible. I guess there are a number of possible reactions ... 1) Practice to get a sense for how much to move back at various distances. 2) When shooting closer and with a larger offset (A to , stop down for greater depth of field. (Look at the work of the great photographers to see how little they shot wide open.) 3) Don't recompose, or recompose very little, and crop as needed. 4) Instead of moving back when recomposing, nudge the focus ring a bit closer after achieving focus. 5) Focus bracket if circumstances permit. 6) Ignore it and hope for the best ; not a solution, but for some photos the exact point of focus may not be that critical, especially if the goal is a soft look and they won't be enlarged too much. 7) Use an autofocus camera with an off-center focus point. 8) Use a "live view" camera that lets you focus off-center. Quote Link to post Share on other sites More sharing options...
250swb Posted January 27, 2012 Share #9 Posted January 27, 2012 since a lot of leica shooters are shooting at 1.4, .95 etc.. is moving back little after recomposing a common practice just wondering because it makes sense but i never heard about it? I would disagree that a lot of Leica shooters are using f/1.4 on a regular basis (although bokeh discussions would make you think otherwise), but many who do still tend to compose with the subject dead centre just because of this problem. So its great that you are thinking about it and not wanting to fall into the same trap. Yes moving slightly is a good technique, I nudge the focus ring to get the same effect, and practice makes perfect. But don't discount stopping down just a fraction more either. Steve Quote Link to post Share on other sites More sharing options...
FrozenInTime Posted January 27, 2012 Share #10 Posted January 27, 2012 Hasselblad 'solved' this on their H4D with 'True Focus' "So the advent of True Focus and Absolute Position Lock in the H4D-40 marks a real breakthrough. It provides a very sophisticated solution by tracking the point of focus as the camera is moved to reframe a shot. The company explains it has used “modern yaw rate sensor technology to measure angular velocity in an innovative way”, resulting in the Absolute Position Lock processor, which forms the foundation of its new True Focus system. “The APL processor accurately logs camera movement during any recomposing, then uses these exact measurements to calculate the necessary focus adjustment, and issues the proper commands to the lens’ focus motor so it can compensate. The APL processor computes the advanced positional algorithms and carries out the required focus corrections at such rapid speed that no shutter lag occurs.” And it works. Once True Focus has locked onto a point of sharpness, the shot can be recomposed to place that point anywhere in the frame, even the extreme corners – which is a big advantage. Read more: Hasselblad H4D-40 camera tested - British Journal of Photography " With Leica M I guess it's down to skill - rocking back and forward to compensate. Quote Link to post Share on other sites More sharing options...
Erik Gunst Lund Posted January 27, 2012 Share #11 Posted January 27, 2012 Are all Leica M lenses flat field lenses? No they are not, to answer my own question. For real world shooting images, I would say that getting the main subject of the image sharp, within DOF, often has much more to do with the 'Flat Field' performance of the lens. So take some test shots to get to know your lenses, one of my 'fast' lenses f/1.2 have a very curved DOF so a rotation without moving back is needed to get a sharp shot. 1 Quote Link to post Share on other sites More sharing options...
tobey bilek Posted January 27, 2012 Share #12 Posted January 27, 2012 Are all Leica M lenses flat field lenses? Almost no Leica lenses have a dead flat field, not even the enlarging lenses with one exception. They give that up to achieve different objectives they deem more important. Exceptions that I know of and can think of this morning: 100 APO2.8 R 65 3.5 only black version, not chrome 50 4.5 large front element enlarging lens (actually a Schneider design} Same for 100 2.8 Focotar 50 2.0 R first version with Elpros attached 60 2.8 R is not flat, amazing but true, but workable at 5.6/8 none of the 50 2.0 up through the 1969 version. Current or last I don`t know I can`t think of a truly flat 90, but they are not bad Bad was 35 3.5 Elmar 400 560 6.8 Leica will admit to them not being flat, but you get light 2 element construction , and ability to use in field without tripod. Put them on a pod and go to 11 and they work ok. The new 50 2.8 and 90 4.0 are outstanding lenses with flat fields, at least reasonably flat, and they work a treat on digital. I have not done rigorous tests because they work on subjects that I use them for. I did a 5 minute test on a new in the box 50 2.0, and it seems ok. I need a tripod and proper lighting to do it correctly. The lens has gone on to its rightful owner. He loves it. Nikon lenses have flatter fields but have so much distortion a Leica designer would be ashamed to put his name on them. Leica have little to no distortion. The micro lenses are an exception, 40 2.8 DX, new 60 2.8 105 2.8 VR . Nikon teles have little to none. The zooms all distort to some degree, usually barrel at wide end and pin at long. I have not tested the new 1.4 G lenses, some day. Right now I am just using them as is. They seem nice. The pro ones are way better than the consumer ones. Photoshop will correct distortion to some degree. You can not fix a none flat field except with multi exposures and focus bracketing, hardly practical. 1 Quote Link to post Share on other sites More sharing options...
Erik Gunst Lund Posted January 27, 2012 Share #13 Posted January 27, 2012 Thanks! A very valued reply! The new 50 2 will probably be my next lens, if you look at how well it performs against the 0.95 1 and 1.4 it's a bargain to get, given I don't shoot so slim DOF with my range finder... Also the new 24 3.4 is praised for having flat field. As to the Nikkor lenses; I mostly agree with your evaluation, I will just add; the 55/3.5 is flat field, was designed for copy work. Noct Nikkor suffers a lot from curved DOF field, but then, it excels in most other fields. The Nikkor zoom 20-35 2.8 AF-D is highly corrected for distortion, don't know why, but thats the reason I have kept it, also for the great IR performance... Quote Link to post Share on other sites More sharing options...
01af Posted January 27, 2012 Share #14 Posted January 27, 2012 The amount of the shift of the plane of best focus will vary greatly with the focusing distance, the angle of the recomposition swing, and the shape of the field curvature. Field curvature can be positive or negative; i. e. the focus for the frame's borders can be closer or farther away than for the frame's center. Curvature may also vary with the focusing distance, e. g. flatter at far distance, more curved at close range (not sure if it will also vary with aperture ... possibly not). This means that compensating for the shift by deliberately leaning back when recomposing is very difficult. In most cases you will vastly over-compensate. It takes a lot of practice to get it right with only one lens used in only a limited range of distances—say, portrait distances. And once you're getting it about right in most of your attempts then you still cannot simply transfer your new skill to another lens or another distance range. 1 Quote Link to post Share on other sites More sharing options...
bocaburger Posted January 27, 2012 Share #15 Posted January 27, 2012 As usual, a font of amazingly detailed theoretical knowledge on this forum! My problem in applying it however, is that without a tripod I'm most likely moving a little front or back as I pivot, without knowing it or being able to judge how much. Not to mention the subject might move a little too. Quote Link to post Share on other sites More sharing options...
dwbell Posted January 27, 2012 Share #16 Posted January 27, 2012 I was intrigued with the same problem and my 35mm f/2. The thread that followed was also incredibly interesting and helpful; http://www.l-camera-forum.com/leica-forum/leica-m9-forum/144706-35-f-2-focus-recompose-rotate.html One very useful bit was the introduction (to me) of the Barnack calculator; Barnack This great little program has an option "Show Recomposition Focus Circle" which shows you visually where you can move your centre focus too without loosing focus. This varies greatly with subject distance (as does DoF) and not so much with f value. It's very educational to play with the numbers, focal lengths etc. In practice it's a bit different though I find - just harder I think. Quote Link to post Share on other sites More sharing options...
stump4545 Posted January 27, 2012 Author Share #17 Posted January 27, 2012 ok, say i am shooting with the .95 wide open and my subject is at 6ft away (as this is how i shot a lot of times) when i focus and recompose is it safe to say that my focus accuracy will be hit or miss at best? up to this point i was just thinking i missed focus but i am now thinking that it is the recomposing that is messing me up with the .95 wide open at under 8ft. Quote Link to post Share on other sites More sharing options...
Erik Gunst Lund Posted January 27, 2012 Share #18 Posted January 27, 2012 It will be hit and miss, even swaying back and forth after focusing will throw you off focus. My procedure for shooting the range finder at critical aperture/focal lengths: Holding breath, have the target in the center of the RF patch, start focusing in one direction I always start at infinity, and just as the target gets into focus in the center, the first time, fire the shutter. If it's a moving target; physical follow the targets paths and keep constant distance. Quote Link to post Share on other sites More sharing options...
stump4545 Posted January 27, 2012 Author Share #19 Posted January 27, 2012 why do you start at infinity and not say at 3ft or the closest focus? is it because your subjects are usually at a far distance? Quote Link to post Share on other sites More sharing options...
Erik Gunst Lund Posted January 27, 2012 Share #20 Posted January 27, 2012 why do you start at infinity and not say at 3ft or the closest focus? is it because your subjects are usually at a far distance? I start from the infinity side so to say, so if target is at 6 ft I start at maybe 7 or 8 ft. As a rule I keep/store the lenses at infinity.., Quote Link to post Share on other sites More sharing options...
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