Serene Life

by garik

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48

Moire Fringe Method Use Bart van der Wolf's moire fringe method (also explained here and here, and archived here): It works by exploiting the interference patterns or moiré between the R/G/B LCD elements and the camera's LCD elements when directly viewed with Life View [sic]. With good optics and perfect focus, the moiré is maximized. ...


20

To check if your camera/lens is having front-focus or back-focus issues you can download a pdf (incl a focus chart) here: http://web.archive.org/web/20121205195820/http://focustestchart.com/focus21.pdf The first few pages describe how AF works and how it can be tested. The actual instructions for testing the AF start at page at page 13.


14

Contrast-Detect-vs.-Phase-Detect Adjustment Method I've been a huge fan of the moiré fringe method suggested by @Eruditass. But in playing with it, I discovered that there's an even better way, if your camera supports contrast-detect autofocus in live view mode. This is, in some ways, a combination of "method 1" and "method 2" of the moiré fringe approach, ...


10

These cameras have microadjustment capability, just not in a user-accessible way. The exact method varies by model. Some have a software feature in an advanced (and secret) "debug" menu — the Pentax K10D, for example, had this. Others have physical adjustment screws or similar (like earlier Canon Rebel models). Or, repair centers may simply use shims. To ...


8

The AF system is designed to focus on the highest contrast within the active coverage area(s) of whatever focus point(s) is(are) selected. If the nature of the lens is one that emphasizes the curvature of the focal plane, then the selected focus point should still be properly focused and the areas at the other focus points might be either front or back ...


8

Generally speaking I think the concept of "lenses that don't focus well on body X" is a misconception. All mechanical and electronic gear is manufactured to certain tolerances...and usually, the more expensive, the tighter the tolerances. If you get two pieces of equipment that are at opposing ends of their range of tolerance, you might end up having to ...


7

You adjust focus on the camera - not the lens. The Canon 60D does not have a micro focus adjustment needed to do this. You may try sending in your camera and lenses in for adjustment together, but it is not something you can adjust yourself on that body. If your 70-200 is significantly slower in max aperture than your 50mm, then it likely doesn't ...


7

No. Well, I've never seen it happen. If it does, I would suspect an imminent mechanical failure. What I did see once is front or back focusing change between focus-distances. In that case the lens focuses well at one distance but is off at another. Since I've only see it once, it may a defect rather than tolerance error.


6

Testing autofocus is hard to get right, so it's a good question. I have used this chart with success: http://pentaxdslrs.blogspot.com/2008/06/part-1-autofocus-adjustment-for-pentax.html (It's a Pentax blog, but the chart and directions are general except for the interactions with the actual camera.) Follow the directions - they're very fiddly, but ...


3

LenAlign is useful and in the right hands can get very good results. Two things are critical when using it. The LensAlign unit must be put together perfectly "square". The camera's actual AF point must be aimed closely enough to the point indicated by the square in the viewfinder to insure the actual point being focused is on the flat part of the target ...


3

I have the 10-22mm lens on a Canon 60D and it works just fine. As mentioned on the previous answer, because of the wide angle there is quite a margin for error in most circumstances — which won't show up on the finished photo. The only lens I've had any focus problems with on the 60D is the Samyang 85mm f/1.4 (manual lens) fitted with the 'EURO' AF-Confirm ...


3

It can be any number of different things. It all comes down to the tolerences that consumer cameras are built to. Typical suspects would include: Lens Element locations Flange-to-film distance Sensor location Focus sensor It is all about the location of the focal plane as outlined here: What is back-focusing?


2

It turns out that the lens was actually at fault (i sent it back to Nikon) I still cant understand quite how the lens can be wrong, surely when its in focus, its in focus?! But thanks for your responses guys :-)


2

Is it normal to be unable to use the outer AF points on a normal to wide angle lens at very large apertures (~f/1.4)? Or should all AF points get the focus right for that point, no matter the curvature of the focal plane? The latter. They will aim to get the focus right for that point. They don't need any knowledge of the curvature of the focal plane. ...


2

I haven't heard of any problems with the 10-22 (or with the 60D in general) but even if I did I wouldn't worry with the 10-22, as long as you're not shooting at the minimum focus distance your depth of field will be huge so accurate focusing is not a worry. In fact I once left my 10-22 set to manual focus all afternoon, I didn't notice because I was still ...


2

They will most likely just adjust the lens, but use the camera body to judge how much to the lens needs adjusting. As a result your other lenses ought to carry on working fine. In terms of what they can actually do to calibrate the lens, then it will vary depending on the lens but in most cases there will be a position sensor in the lens which detects where ...


2

The Nikon D600 has AF fine-tuning and it works exactly the same way as on the D800. It will adjust focus front or back a number of tiny steps. The step size is unspecified so you have to do it by just trying. If your lens is severely off, it is possible that no number will be suitable and you will have to have it calibrated for your camera by Nikon. Note AF ...


2

Part of the problem is that you are at infinity. The reason that infinity is shown as a range is that it does not remain constant. Environmental conditions can actually impact (fairly significantly) what the actual point you need to focus the lens on to be focused on a point infinitely far away. The value that gives best results can change from one ...


2

As far as I'm aware the answer is no. If its infinity that you are most bothered about, i'd find where the focus is best and mark it on the ring manually, a little bit of white paint downwards from that line to match the pointer line below would be good enough.


1

If you're asking so you can do it yourself, sorry but you're out of luck. The following only applies to DSLR cameras. When adjusting lenses, collimators are used and can cost tens of thousands of dollars. They are finely tuned instruments. A collimator optically emulates infinity (over 100 meters or so) and come in different sizes. It shines light through ...


1

20mm out is a massive amount and not explicable by any normal calibration errors. If it is really back-focusing by 20mm (2cm) then something is faulty. If the D800 is OK with other lenses it's liable to be the lens that is faulty. BUT If the lens is OK with other cameras it's liable to be the camera. BUT if both the above apply, which is how Murphy loves ...



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