[UncleVanya]

Simple option is a ruler with a printed target attached to a book positioned in parallel to a mark on the ruler. Focus on the target on the book.

[Alex645]

is there a best distance for calibrating focus, and is it different for each FL?

According to LensCal, they recommend no less than 50x the focal length and with 200mm or greater, no less than 25x the focal length.

If, however, you shoot landscapes or typically at infinity, calibration tools are impractical and I would run the test for infinity. You can always shoot LiveView as the comparison critical sharpness image that youʻre trying to achieve with the OVF.

[Digitalis]

One final observation...with zooms different adjustment may be needed at different focal lengths.

It is also important to note with zooms if you adjust one focal length, that adjustment may affect accuracy at other focal lengths as well.

[stevebrot]

It is also important to note with zooms if you adjust one focal length, that adjustment may affect accuracy at other focal lengths as well.

That is probably why the remedy of last resort is a trip to the lens manufacturer for calibration of the lens itself against a specific body.


Steve

[From1980]

On sensor focus, as used on mirrorless camera and liveview for DSLR, gives you perfect focus without the need for correction or calibration. Until recently, this on sensor focus also had its own drawbacks. But the most recent iterations are now quite good. IMHO, the precision of this on sensor focus is probably the biggest advantage of mirrorless camera.

Thanks for discussion. Given my own preferences and shooting style then, I could save a lot of money by skipping most of the current crop of AF lenses. I'll make do with what I have, keep an eye out for occasional irresistible prices(LBA), and continue to shoot film as long as I can while awaiting reliable AF technology.

[clackers]

Thanks for discussion. Given my own preferences and shooting style then, I could save a lot of money by skipping most of the current crop of AF lenses. I'll make do with what I have, keep an eye out for occasional irresistible prices(LBA), and continue to shoot film as long as I can while awaiting reliable AF technology.

I'm not sure you've got this in proportion, From1980.

I shoot manual a lot on my A7 (I've even done sports), because I put Pentax lenses on it all the time, and my K-30 has a split-image viewfinder, too.

But they're no substitute for AF - MF is niche use for me, and I bet most people *never* do it.

Remember, fine tuning is something you only need to do once with each lens and body combination, and only if there's a problem. Let's not claim microadjustment's a bigger problem than it is.

[From1980]

I'm not sure you've got this in proportion, From1980.

It was mostly a tongue-in-cheek comment but my manual focus lenses really never needed adjustment, even once.... I know, LOL.
Seriously, the way I usually like to shoot doesn't include the uses I feel AF is suited for in the first place. I want to continue shooting film and when I use my DSLR it's more often than not for the same slow, deliberate approach of nature and landscape shots. Also, especially for most outdoor and landscape shots, when I'm using wide angles the lens' depth of field scale (remember those) is used to set the lens for focus with my chosen aperture.
A good point was made above about modern AF not handling large apertures well and that pretty much is what I shoot the rest of the time, especially indoors with available ambient light.

I may some day acquire a K-1 and I understand that it could be better at AF but the price means I'll have to wait a while.
A used 645D might suit me better before then though and it would be used pretty much the same way I always used medium format film.

[Digitalis]

they're no substitute for AF - MF is niche use for me, and I bet most people *never* do it.

How they did it in the days without AF will utterly confound Millennials.

[From1980]

How they did it in the days without AF will utterly confound Millennials.

Oh yes, the Millennials. I have some in my family. They are the ones who ask how you can tell if an image is in focus.

[clackers]

How they did it in the days without AF will utterly confound Millennials.

Yeah, I'm not sure how they cope with low contrast concert photography, astro, macro, picking out a subject amongst distracting elements in a sports or wildlife job ... but there you go.

[Digitalis]

Oh yes, the Millennials. I have some in my family. They are the ones who ask how you can tell if an image is in focus.

oh, that is precious.

[CarlJF]

Thanks for discussion. Given my own preferences and shooting style then, I could save a lot of money by skipping most of the current crop of AF lenses. I'll make do with what I have, keep an eye out for occasional irresistible prices(LBA), and continue to shoot film as long as I can while awaiting reliable AF technology.

Actually, modern AF systems are vety reliable and will get the job done under most usual shootiing situations. It's just that we should not expect it to be the bestvway to go 100% of the time under all conditions...

It's somewhat similar to autoexposure. Most of the time it will do just fine and makes your life easier. But there are still many situations that will fool the system and require the photographer to manually compensate or switch to M mode. This doesn't mean that AE is unreliable or useless. Just that the user must understand how it works and recognize the situations when it might be better to use manual exposure.

[From1980]

oh, that is precious.

This would be an ideal situation to use one of the new texting acronyms I've recently been given by my Facebooking wife.

IOTTMCO -apparently means "Inherently obvious to the most casual observer"

[Wild Mark]

IOTTMCO -apparently means "Inherently obvious to the most casual observer"

you made that up didn't you

[mee]

They all need to be checked, although adjustments might not be required for all.

Indeed. I have several lenses that are sharpest at 0 AF micro-adjustment (no adjustment required). I have a few others that need fairly heavy adjustment (5 to 10 ticks).

When you buy a new lens, it is a good idea to test it at different distances (minimum, somewhere in the middle, and infinity) as well as both ends of a zoom range for correct focus. If it is too far off, beyond the range of the micro-adjustments, I'd send it back for another copy.

That might seem tedious, it is. It is probably also nitpicky. But I'd rather have the best performance possible than settling for subpar..



With a zoom lens, if you don't want to go through all the rigamarole, just zoom to the focal length you'll use most often and test there. It might throw off the focus at other places in the focal range of the lens, but it is best to have the.. best.. performance where you'll use it most.

My ultra nitpicky test goes something as follows: set the camera on a tripod, set the camera to use a 2 second timer, set the camera to use the center focus point, set the lens to the focal length most used, set the AF micro-adjustment to -10 in the camera settings, ensure you're using the smallest aperture value (f/1.8 or f/2.8 but NOT f/5.6 f/8 or f/11 etc), focus on a flat surface parallel to it (make sure you are aligned to it otherwise one side will be softer), turn the focus ring to minimum focus (closest it will focus), let the camera focus for you (half press shutter button), gently press the shutter button down fully and let go, let the camera take a photo. Now go back into settings, and adjust the value to -8, do the rest of the steps above, wash rinse repeat to -6, -4, -2, 0, +2, +4, +6, +8, +10.

NOW you should have a collection of 11 images. Load those on your computer, and cycle through at 1:1 view each image until you find the one that is sharpest. Look in the EXIF data for the AF micro-adjustment value to determine which value is which or keep a record as you are taking photos as to which photo corresponds to which AF m-a setting. Then dial that back in for that lens. tada.

Once you adjust a lens, you'll probably get the hang of it and it will become quick work whenever you get another lens or want to test at a different focal length.

---------- Post added 11-12-16 at 09:45 PM ----------

Attempting calibration at infinity distance is not a good idea. There are multiple threads on this site where a user post complaints of their inability to attain sharp focus at distance despite exhaustive attempts to calibrate. Blame is usually placed on the camera or lens with the usual outcome being multiple trips for camera/lens repair and eventual sale of both. Truth is that the focus mechanism (poor precision at distance) and the atmosphere (poor contrast and distortion at distance) work against one's best efforts.

Infinity is preferred if most of your work is done at infinity. Just try not to test on a hot day.

I see you appear to be alluding to my bout with Precision of my 16-50mm. But the issue wasn't because I was testing at infinity. The issue was the lens would not physically focus at infinity (even through attempting to manually focus -- there wasn't enough length on the focus ring to turn it to get to infinity). So that was a flaw of that copy of that lens. The replacement lens they shipped me focuses fine at infinity.