[mroeder75]

Recently, I found one of my lenses was way out of calibration since the day I purchased it used three years ago. I thought the lens was soft. In the past two weeks, I calibrated it indoors. It is a Sigma 30mm 1.4 DC. Now that I see how it works I want to keep it. I found it has great center point sharpness. Maybe because it was out of calibration was the reason it was put up for sale 3-years ago. As you get to the margins it is not sharp.

My question: Do you calibrate each lens? Or do you only calibrate after you have taken many photos and thought, "This lens is suspiciously soft?"

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Last edited by mroeder75; 12-24-2022 at 12:31 AM.

[Snafu711]

For me lens-calibration is a remedy I use only when needed. None of my Pentax lenses requires calibration.

The one lens I have trouble focusing is the Sigma 35/1.4, which seemed to need calibration. I used the Sigma in-lens calibration to fix that, saw improvements but still have a lot of soft pictures. The lens itself is razorsharp but focusing often stops too early. Depending on whether I focus from near to far or far to near the calibration needed to close that gap has a different sign. My conclusion is that this behavior is not a calibration issue but rather a limitation in the cooperation between lens and camera. Using the lens wide open requires precision and shows all lack thereof.

My fix is to trigger focus multiple times, until there is no refocusing - then the the focus is usually spot-on.

I could imagine the your Sigma lens is behaving similarly.

[Digitalis]

My question: Do you calibrate each lens?

Lens Calibration is dominantly body dependent*, usually I calibrate a lens for a specific camera body and the first thing I calibrate is the infinity focus point - once that is properly set, AF calibrations are checked for accuracy and repeatability. To calibrate AF I use Datacolour Spyder LensCal - I find it produces repeatable and reliable results when used properly. The standard short ruler is fine for lenses around 100mm anything approaching 200mm and over the longer ruler is often needed.

Or do you only calibrate after you have taken many photos and thought, "This lens is suspiciously soft?"

In my line of work in commercial photography there is little to no chance of a re-shoot. I calibrate things first to make sure there are no unexpected surprises.

* Though with some lenses such as the Sigma 18-35mm f/1.8 ART which flatly defied any attempt at AF correction, I had to resort to getting the lens calibration puck from Sigma which to date is by far the most expensive lens cap I have ever bought. Unfortunately the AF calibration software from Sigma didn't allow me to correct for the precise distance where this lens had the most significant problems so YMMV.

[BarryE]

Lens Calibration is dominantly body dependent*, usually I calibrate a lens for a specific camera body and the first thing I calibrate is the infinity focus point - once that is properly set, AF calibrations are checked for accuracy and repeatability. To calibrate AF I use Datacolour Spyder LensCal - I find it produces repeatable and reliable results when used properly. The standard short ruler is fine for lenses around 100mm anything approaching 200mm and over the longer ruler is often needed.

Personally, I've found an alternative lens calibration method that works for all focal lengths from 15mm to 300mm and better reflects the focussing distances I use. I've become suspicious that testing with a ruler inside ie at a short distance can be problematic for some body/lens combinations. So I lay a ladder on boxes. Fix tape, ie hazard tape, which has regular markings on to the ladder. Then vertically set up a focussing target on the ladder about halfway along its length. I then have both the tape's graduations and the ladder's rungs to check the back/forward focussing. The advantage of this setup is I can check te AF accuracy from both near and distance.

I calibrate for every new lens for each body. I then record it in case I lose the camera settings. I've also spot checked occasionally, especially after firmware updates, as settings have sometimes seem to have drifted.

Of course now most of my photography uses manual focussing I do wonder why I bother

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Last edited by BarryE; 12-24-2022 at 02:58 AM.

[JensE]

My question: Do you calibrate each lens? Or do you only calibrate after you have taken many photos and thought, "This lens is suspiciously soft?"

I know that both of my current cameras are not spot-on, one even after sending it in another time because a repair left it completely miscalibrated. Therefore, I try to calibrate each lens on both cameras right when I get it. Not such a frequent event anymore, my lens turnover has slowed down quite a bit.

[savoche]

Some years ago I calibrated (or rather, checked) several of my lenses after reading of members here claiming that all their lenses needed calibration. It might be that I'm not very picky, but none* of my lenses needed calibration. So pretty much this:

For me lens-calibration is a remedy I use only when needed. None of my Pentax lenses requires calibration.

* I needed to calibrate my K-3 with the FA31 after the lens had been in for repair. On the K-1 no adjustment is needed.

[pschlute]

Sometimes it is the lens that needs calibration, sometimes it is the camera. Sometimes both.

My first K-1 had a AF sensor that required a general +7 to give accurate AF with all lenses. A few lenses required a bit more or less.

My current K-1 II requires no general adjustment on the lenses I have used so far.

[Medex]

I calibrate all lenses and check/repeat procedure time to time

[AfterPentax Mark II]

My question: Do you calibrate each lens? Or do you only calibrate after you have taken many photos and thought, "This lens is suspiciously soft?"
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My answer: Never! (certainly not with a Pentax branded lens and a lens that needs calibrating usually ends up in my museum with my defective Super A and all film camera's!)

[mroeder75]

What a variety of answers. Seems like most of us have good experiences with Pentax lenses being calibrated to the camera properly. In view of the responses about non-Pentax lenses I checked the focus on one other non-Pentax lens I purchased recently, and its focus is good.

My Pentax lenses focus adequately, so I am not checking them.

[Ron Boggs]

Half dozen Pentax DSLR's and a couple dozen lenses, all fine no adjustments needed for those times when autofocus is used. Probably 80% manual focus or preset fixed focus for my types of shooting.