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Calibrating a zoom lens
May 5, 2024 11:08:55 #
gvarner
Loc: Central Oregon Coast
I read that calibrating a zoom lens is only good at the focal length where it was calibrated. Is that correct?
May 5, 2024 11:11:14 #
gvarner wrote:
I read that calibrating a zoom lens is only good at the focal length where it was calibrated. Is that correct?
Mostly, although some of the final more advanced DSLRs provided the ability to set two focal lengths per zoom lens.
May 5, 2024 11:15:59 #
CHG_CANON wrote:
Mostly, although some of the final more advanced DSLRs provided the ability to set two focal lengths per zoom lens.
Bummer, only two?
What about all the other positions in-between.
Oh, wait, I'm not worried about a foot or two.
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May 5, 2024 11:33:20 #
Orphoto
Loc: Oregon
Mostly correct. It takes a fair amount of testing to figure out. If lucky one correction suffices for the range. If less lucky you have to compromise by picking one or two and calling it a day.
May 5, 2024 12:56:13 #
Most cameras allow for only one correction per lens and it is applied to the entire lens.
Therefore you usually apply correction at the long end.
If you decide to do it, test well afterward to be sure you have not created a different problem.
Your camera manual should tell you if your camera allows more than one.
Therefore you usually apply correction at the long end.
If you decide to do it, test well afterward to be sure you have not created a different problem.
Your camera manual should tell you if your camera allows more than one.
May 5, 2024 13:13:16 #
CHG_CANON wrote:
Mostly, although some of the final more advanced DSLRs provided the ability to set two focal lengths per zoom lens.
End result being that two FLs are then made accurate, at one particular focus distance for each. Example is knowing that my 28-135 is accurate for 10 feet at 35mm and 25 feet for 110mm ... and acoarst other settings that are fairly close to those, like 15 feet at 40mm, do also benefit.
If I need great detail, Ill use LV focus (AF or MF) and stop down a few stops.
I shouldve written the above all in past tense. Ive moved on from SLRs. Somewhere in the late 1980s new model SLRs began losing their effectiveness. It was slight at first, but then it snowballed. The cavalry finally arrived in the form of the Sony Nex-7 ... and all new lenses.
May 5, 2024 13:25:50 #
MJPerini wrote:
Most cameras allow for only one correction per lens and it is applied to the entire lens.
Therefore you usually apply correction at the long end.
If you decide to do it, test well afterward to be sure you have not created a different problem.
Your camera manual should tell you if your camera allows more than one.
Therefore you usually apply correction at the long end.
If you decide to do it, test well afterward to be sure you have not created a different problem.
Your camera manual should tell you if your camera allows more than one.
Actually the menu for the task will show you whether two FLs can be calibrated. I was setting up a new camera and the menu had openings for two FLs.
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May 6, 2024 05:22:58 #
A piece of advice. If you have a lens that needs calibration, send it to the distributor. In my more than 50 years photographing I never had to send a lens for calibration, zoom or prime.
May 6, 2024 07:31:42 #
camerapapi wrote:
A piece of advice. If you have a lens that needs calibration, send it to the distributor. In my more than 50 years photographing I never had to send a lens for calibration, zoom or prime.
50 years ago auto-focus was not as prevalent.....
May 6, 2024 07:38:15 #
billnikon
Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont
gvarner wrote:
I read that calibrating a zoom lens is only good at the focal length where it was calibrated. Is that correct?
YES. That's why I never bother calibrating a zoom lens, it is not worth it.
And many professionals caution not to calibrate any lens, because most of the time an amateur will make the lens worst by calibrating.
Personally I have never calibrated a lens. I have won many awards and have done many shows. And my images are all sharp.
Some advice, your shutter speed should be at least that of the max. focal length of your lens, ie. is your shooting a 60-600mm lens, then your shutter speed should be at least 1/600 sec.
Hold your lens just behind the lens hood on the bottom of the barrel.
Hold your elbows in to your body, hold the camera against your head. This will create a three point contact which will help keep your lens steady.
Stop down your lens 2 to 3 stops.
By doing this you will find you get sharp images without having to calibrate.
Calibration should always be done by a professional.
Again, you should NEVER have to calibrate a lens, especially a zoom lens.
May 6, 2024 07:54:30 #
Zoom lenses NEVER can perform optical quality as to Macro Micro and Enlarger lenses (true prime lenses). In 1960's there was hardly any zoom lens that were usable in still photography. Movie and TV cameras could get by
poor images because human eyes could no see how poor images they were. But in 21st century, it is great to see super computer design and new optical glass, they can handle 4K even 8K line images, the TV lines was 525?
Enjoy digital.
poor images because human eyes could no see how poor images they were. But in 21st century, it is great to see super computer design and new optical glass, they can handle 4K even 8K line images, the TV lines was 525?
Enjoy digital.
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May 6, 2024 08:21:05 #
ken.toda wrote:
Zoom lenses NEVER can perform optical quality as to Macro Micro and Enlarger lenses (true prime lenses).....
Doesn't bother some of us.....
May 6, 2024 09:02:00 #
gvarner wrote:
I read that calibrating a zoom lens is only good at the focal length where it was calibrated. Is that correct?
Mostly correct - but I would not obsess over it. Most DSLR cameras calibrate at only one focal length - but SOME newer ones do two. If you only have ONE CAL point, on a zoom lens, decide what focal length ( and distance ) you want to be the most perfect - otherwise do it on the longest FL. If you have two cal points, then best practice dictates do the shortest and longest lengths and at corresponding distances. Distances do matter ! but probably less so than focal length. Naturally, this is a more important concern for longer/faster zooms - (200mm +) otherwise, not so much. If you are uncomfortable adjusting the cal yourself then farm it out.
.
May 6, 2024 10:44:54 #
Longshadow wrote:
50 years ago auto-focus was not as prevalent.....
Real facts can be soooooooooo annoying ......
May 6, 2024 13:09:27 #
gvarner wrote:
I read that calibrating a zoom lens is only good at the focal length where it was calibrated. Is that correct?
Go mirrorless and forget about calibration!
bwa
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