Target distance for zoom lens calibration: I am getting ready to calibrate my nikon 70-200mm f2.8 VRII lens with my D7100, and have not been able to find an answer to the following...

GWZ Loc: Bloomington, IN

I am getting ready to calibrate my nikon 70-200mm f2.8 VRII lens with my D7100, and have not been able to find an answer to the following question.

The bulk of my images are of plants and insects that land on them. I typically shoot at 200mm using f/8+ for some DoF from about five feet away from the target. Everything I have seen for the target calibration distance for my camera/lens combination set at 200mm suggests a target in the 16 foot range.

My question is:

Since the vast majority of my images are actually shot at about the five foot range, and given that at 5 feet the DoF is pretty shallow, should I calibrate the camera/lens using a target distance of five feet, or should I calibrate it using the 16 foot range that is suggested, even though I will shoot at five feet?

An alternative I thought of is to get the calibration adjustment number at both distances (five feet and sixteen feet), and then recalibrate the focus depending on the type of shooting I am planning on doing that day.

Thanks in advance for any thoughts and/or real-life experiences you can share.

Gary Zakian

imagemeister Loc: mid east Florida

GWZ wrote:

I am getting ready to calibrate my nikon 70-200mm ... (show quote)

To answer your question, IMO you should be calibrating at 5 feet . But I would also check it at 16 feet. and see if there is any difference. If there is a difference, you may want to consider a compromise setting splitting the difference as shooting at f8 at 5 feet will cover up some focus errors.

At what distance are you most likely to be shooting at f2.8 - may also be a consideration for you.

CO

I use the DataColor SpyderLensCal target to calibrate my lenses. They recommend 25 to 50 times the focal length. I've been doing 5 to 10 times the focal length. If I use their recommended distances, I have to zoom in a lot on the computer in order to see the lines on the target. I took a screen shot of the page from their instruction manual for the SpyderLensCal. I'll post it below.

The 16 feet that you stated is the same as the minimum distance they have in their chart for a 200mm lens.

(Download)

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

GWZ wrote:

I am getting ready to calibrate my nikon 70-200mm ... (show quote)

If you feel your lens and camera need calibration, you are wasting your time adjusting your lens for a single focal length and distance. When you shift the focus, you do it for all focal lengths and distances - you just move the goal post so to speak - are you sure you really want to do that?

If you have tested your lens and found it to be off, send the camera and lens to Nikon, specifying that they are to test both and if the lens is in spec but the body is not, they are to adjust only the body. They will use software and adjust things that you have no access to that will improve the focus performance at all distances and focal lengths. There is no way you can even come close with the AF Fine Tune in your camera, and there is a good chance you will adversely affect AF performance for other situations.

TriX Loc: Raleigh, NC

Maybe some experimentation (and keeping accurate records) is in order. When I cal my lenses (using Focal), I verify the suggested MFA by shooting a standard resolution target at the various FLs and distances with MFAs on either side of the suggested correction to verify the correction. After doing this many times, I've become convinced of the accuracy of the system, and I also have a feel for any adjustments to make at intermediate settings between the wide and tele zoom settings and distances. I come from a long background of calibrated equipment and precise measurements, so I absolutely believe in knowing that what I'm measuring is not only precise, but accurate, in order to get the most out of my equipment. I'm not willing to settle for 90-95% of the available performance of a system when accurate tuning/calibration can yield the last 5-10%.

Psergel Loc: New Mexico

CO wrote:

I use the DataColor SpyderLensCal target to calibrate my lenses. They recommend 25 to 50 times the focal length. I've been doing 5 to 10 times the focal length. If I use their recommended distances, I have to zoom in a lot on the computer in order to see the lines on the target. I took a screen shot of the page from their instruction manual for the SpyderLensCal. I'll post it below.

The 16 feet that you stated is the same as the minimum distance they have in their chart for a 200mm lens.

Thanks for posting this!

rdubreuil Loc: Dummer, NH USA

GWZ wrote:

I am getting ready to calibrate my nikon 70-200mm ... (show quote)

"An alternative I thought of is to get the calibration adjustment number at both distances (five feet and sixteen feet), and then recalibrate the focus depending on the type of shooting I am planning on doing that day."

You've answered your own question. Calibrate for both types of shooting and save to your shooting banks. One for the close stuff and one for the distant range, then it's just a single menu change rather that having to dive into your menus to make the adjustment, a lot less clicks of the menu and more clicks of the shutter release.

imagemeister Loc: mid east Florida

rdubreuil wrote:

"An alternative I thought of is to get the ca... (show quote)

BUT, you will have to REMEMBER to do it ! - and you may have your memory slots already taken by other shooting scenarios....

mborn Loc: Massachusetts

imagemeister wrote:

To answer your question, IMO you should be calibrating at 5 feet . But I would also check it at 16 feet. and see if there is any difference. If there is a difference, you may want to consider a compromise setting splitting the difference as shooting at f8 at 5 feet will cover up some focus errors.

At what distance are you most likely to be shooting at f2.8 - may also be a consideration for you.

Right On Check Steve Perry's video https://www.youtube.com/watch?v=5cHhrWF-pqM&feature=em-subs_digest

BebuLamar

Gene51 wrote:

If you feel your lens and camera need calibration,... (show quote)

I never fine tune the AF on my camera but as I see there is only 1 variable that I can change and to me that insufficient for calibrating so I never bother to do that.

RWR Loc: La Mesa, CA

GWZ wrote:

I am getting ready to calibrate my nikon 70-200mm ... (show quote)

My experience has been that when the subject is in sharp focus on the focusing screen, it should be in sharp focus at the focal plane.

Tigger1 Loc: Surrey, BC Canada

GWZ wrote:

I am getting ready to calibrate my nikon 70-200mm ... (show quote)

sandiegosteve Loc: San Diego, CA

Lens align has a calculator (click the distance tab). http://michaeltapesdesign.com/lensalign.html

amfoto1 Loc: San Jose, Calif. USA

Gene51 wrote:

If you feel your lens and camera need calibration,... (show quote)

Isn't Nikon's AF Fine Tune same as Canon's Micro Focus Adjustment feature?

With the more recent Canon cameras with MFA, any zoom lens gets two adjustments: one at each extreme of the focal length range.

Targets should be positioned 25X to 50X the focal length, is what I've always heard and read, too.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

BebuLamar wrote:

I never fine tune the AF on my camera but as I see there is only 1 variable that I can change and to me that insufficient for calibrating so I never bother to do that.

Absolutely. It's fun to play with, especially when doing a portrait session when you can deliberately defocus the lens to produce a soft image. But that is about all the in camera fine tune is good for. If you change the focus point it will affect all of your focus at all focal lengths and distances. I don't want that.