Puzzling EXIF Data: Check out the EXIF data connected to these test images that were hand held with my D600 with the Sigma 150-500mm lens. It was zoomed out to 500 showing on the lens...

Nikon_DonB Loc: Chicago

Check out the EXIF data connected to these test images that were hand held with my D600 with the Sigma 150-500mm lens. It was zoomed out to 500 showing on the lens barrel hashmarks but the EXIF data only shows a focal length of 300mm. The last one was taken last night on the tripod.
A friend suggested lens creep. Not on these test images. I held the lens at the 500 mark. Getting me crazy. The size of the moon's image also looks comparable to the size achieved from my 70-300mm. I bought the lens refurbed from Sigma a year ago. Why????

Any ideas, Experts?

(Download)

Apaflo Loc: Anchorage, Alaska

Nikon_DonB wrote:

Check out the EXIF data connected to these test im... (show quote)

Interesting. What does it register when set to minimum focal length, and how do the images there compare in size to those shot with the 70-300mm at that focal length? (Don't do this test with a focusing distance of less than may 100 to 200 feet, as lenses with "Internal Focusing" designs exhibit "focus breathing" and may not have the same focal length when focusing a shorter distances.)

Nikon_DonB Loc: Chicago

Apaflo wrote:

Interesting. What does it register when set to minimum focal length, and how do the images there compare in size to those shot with the 70-300mm at that focal length? (Don't do this test with a focusing distance of less than may 100 to 200 feet, as lenses with "Internal Focusing" designs exhibit "focus breathing" and may not have the same focal length when focusing a shorter distances.)

I really didn't try it at 150. I was concerned with the maximum reach which wasn't making it for some reason. Thanks for the idea though.

SonnyE Loc: Communist California, USA

Getting you crazy.
Sometimes my wife sez, "_____ drives me crazy."
My standard reply was, "Short trip."
I had to stop saying that. She was getting crazy about it. :shock:

I wouldn't have a clue about your lens and the exhibited EXIF data.
My guess would be the lens and processor can't figure out what it is with the moon being so very far away and the lighting low.
Was your battery charged up good?
Electronics can get goofy on less than a happy power level.
Other than that, we are probably both crazy anyway. :lol:

What's with that line in the moon shot? Could that be throwing things off? (Branch? Hair? :?: )

Rongnongno Loc: FL

Nikon_DonB wrote:

Check out the EXIF data connected to these test im... (show quote)

I have a single question...
D600 = FF
Lens = ??? DX?

If so you have your answer, the camera adjust automatically to the lens.

Apaflo Loc: Anchorage, Alaska

Rongnongno wrote:

I have a single question...
D600 = FF
Lens = ??? DX?

If so you have your answer, the camera adjust automatically to the lens.

A 500mm focal length would still be 500mm.

Nikon_DonB Loc: Chicago

Rongnongno wrote:

I have a single question...
D600 = FF
Lens = ??? DX?

If so you have your answer, the camera adjust automatically to the lens.

Thanks Ron but here's a paragraph from Sigma's site. They say it's designed for FF. DX was a good idea though. It actually crossed my mind too.

The Sigma 150-500mm F5-6.3 is ultra telephoto zoom designed for Full Frame sensors but may also be used with smaller APS-c size sensors with a corresponding effective increase in focal length to about 255mm to 850mm on the Sigma SD format. An Optical Stabilizer (OS) allows for handheld photography even in low light scenarios, while a Hyper Sonic Motor (HSM) ensures quiet, high speed, and accurate autofocusing. This unique lens is an excellent optical performer featuring three SLD (Special Low Dispersion) glass elements for optimum color correction and sharpness throughout the entire zoom range, rear focusing system corrects for fluctuation of aberration due to focusing. It compact size of a mere 10 inches and weight of only 4 pounds for its focal length make it a must have for any camera bag.

Nikon_DonB Loc: Chicago

SonnyE wrote:

Getting you crazy. br Sometimes my wife sez, "... (show quote)

Thanks SonnyE. It was a power line. It wouldn't affect anything since camera was set to spot metering and focus was on the moon..

Apaflo Loc: Anchorage, Alaska

Nikon_DonB wrote:

DX was a good idea though. It actually crossed my mind too.

It's a nonsense idea! :-)

If the focal length is the same, either a DX or an FX lens will produce exactly the same size for any given object. That is, if the object, at a specific distance, is 2000 pixels wide, it will be exactly that with the same focal length in either DX or FX modes on the camera and with either a DX or FX model lens.

The FX/DX label relates only to the physical size of the sensor, not to the focal length of the lens.

And the Exif data would properly report exactly the same focal length too.

Psergel Loc: New Mexico

If the size of the image is the same as what you get with your 70-300 set to 300, I would have to assume that your 150-500 isn't zooming out to 500.
If the image is larger than what you get with your 70-300 set to 300, then your camera and lens aren't communicating properly.

The first thing to do is to take shots of the same thing from the same spot with both lenses at max (300 and 500). If they are actually pretty much the same size.......call Sigma.
If the 500 is, in fact, larger....try cleaning the contacts,on the lens and the camera lens mount.
Also....do you have the latest firmware on your camera?

The EXIF data indicates that the camera recognizes the lens right down to the last character of its complex name. So it's reasonable to assume that you should be seeing the correct focal length in your exif

oldtigger Loc: Roanoke Virginia-USA

Nikon_DonB wrote:

Check out the EXIF data connected to these test images that were hand held with my D600 with the Sigma 150-500mm lens. It was zoomed out to 500 showing on the lens barrel hashmarks but the EXIF data only shows a focal length of 300mm. ...

did you program the focal length into your camera?

Gifted One Loc: S. E. Idaho

Perhaps contacting Sigma would be in order. I find that makers are very helpful. J. R.

jcboy3

Nikon_DonB wrote:

Check out the EXIF data connected to these test im... (show quote)

The size of the moon in a FF image is equal to (focal length)/109. See http://home.hiwaay.net/~krcool/Astro/moon/howtophoto/

At 500mm, that's 4.587mm. In your first picture, the moon is about 765 pixels (I measured with an image program), so in mm it is 24*765/4016=4.57mm. On that basis, I would say that the picture was taken at 500mm.

Can't say much about the second picture, but be aware that the Sigma 150-500 has very heavy focus breathing, so at close focus the actual focal length is much shorter than reported.

In your case, the reported focal length appears to be incorrect. That could be an electronics problem with the lens. Try cleaning the contacts; see if that helps. Otherwise, I would get the lens serviced. Errors in the electronics could adversely affect performance, especially image stabilization.

Picdude Loc: Ohio

Nikon_DonB wrote:

Check out the EXIF data connected to these test im... (show quote)

A question - You mentioned that you bought this lens a year ago. Is this problem new, or are you just now noticing the issue? Either way, a call to Sigma sounds like it's in order, although the warranty is likely to be out a year after the purchase of a refurb lens.

jerryc41 Loc: Catskill Mts of NY

Nikon_DonB wrote:

Check out the EXIF data connected to these test im... (show quote)

This calls for several hours of experimentation and documentation. See, I just gave your day purpose.

Use different lenses and different focal lengths and see what the EXIF says. That will give you a base for comparison. You're comparing two things here - mechanical movement/setting of the lens, and electronic interpretation of the lens's position.

I can't wait for your report!