RegisG Loc: Mid-Tennessee

I'm still working on my new tamron. I've asked question before about noise but a couple people pointed out that my focus was not correct. And, they are correct.

I get perfectly sharp photos with my 70-200 L lens but, that's a long way from 600mm.

Below are the same shot on tripod with remote shutter at 300, 400, 500, & 600. All setting remain the same and these jpegs are straight from camera.

Please let me know your thoughts. Do I need to send for repair or is this what I should expect (1.6 sensor makes this up to about 900mm I think).

I may have to upload in 2 or 3 steps.

RegisG

Thanks,
Regis

300mm

(Download)

400mm

(Download)

500mm

(Download)

600mm

(Download)

Fkaufman3 Loc: Florida, LA ie lower Alabama

How high was the ISO?

gawler Loc: rural south australia

does look out Regis , i have the same lens and canon 7d 6d and 5d mark 3
and had to calibrate lense to all three bodys , now its fine on all of them
what sort of body are you useing
and yes as stated above settings can make a big differnce

Searcher Loc: Kent, England

ISO 100

300mm sharp. 400 - 600mm progressively less sharp

When you said same settings, did you refocus as you zoomed in?

Bret Loc: Dayton Ohio

With a 600mm long lens and a shutter speed at 1/80th a second....I'd say breathing....shutter button pressure more like it.
Welp....disregard....maybe wind or movement of some kind.

RegisG Loc: Mid-Tennessee

iso = 100

RegisG Loc: Mid-Tennessee

Now THAT is something that I need to learn to do.

I have Canon 70D

Thanks,
RegisG

RegisG Loc: Mid-Tennessee

Yes, I re-focused each time trying to cent spot on tree.

Thanks,
RegisG

RegisG Loc: Mid-Tennessee

I was on tripod, inside house. I'll raise shutter to 240 or so and try again.

Thanks,
RegisG

MT Shooter Loc: Montana

Not bad at 400mm. Not good at 500mm. Terrible at 600mm. Definitely a fall-off in sharpness.
Tamron is offering a firmware upgrade on these lenses that's supposed to make them all better. Why they don't just put that firmware in the lens before its shipped from the factory I will never know.

RegisG Loc: Mid-Tennessee

I'll check to see if my serial number needs it or has it.
Thank you,
RegisG

naturepics43 Loc: Hocking Co. Ohio - USA

I feel your pain. I went thru the same thing when I got my Sigma 150-500 about 2 years ago. My photo's weren't even close to others using same lens.

After carefully looking at the first image, it looks like you were shooting at a downward angle on the tree trunk. The bottom of the tree trunk is much sharper than the top.
I think you have TWO problems with these photos. Shutter speed TOO SLOW & lens is back focusing.

Here is a very easy way to check focus accuracy: set up 7 soup cans at a 45 degree angle (about 6 inches apart) on the picnic table outside. Set up your camera on a tripod about 50 or 60 feet away. Focus on the THIRD soup can. Use aperture priority ,f 8, ISO 400 & set lens to 500mm. Take photo & examine on computer. The third can you focused on should be sharp. If the fourth can is sharper, the lens is back focusing & this is your problem. If your camera has "focus adjust" feature, read manual on how to do it. It's trial & error this way but it will work.

Good luck!!

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

Before you start making AF fine tuning adjustments, try a simple test.

1. Put the lens on a tripod
2. Turn off stabilization (it will remove motion blur, but it could affect lens resolution)
3. Put a piece of paper with printed writing on it on a surface that is parallel to the sensor plane, a distance away - similar to your tree.
4. Take a pair of images at each focal length, using live view autofocus for one, then use phase detect (normal autofocus) for the second. Use raw for this test on both images.
5. When you have downloaded the images to your computer, evaluate your images after applying a small amount of capture sharpening (about 25%) and no noise reduction. Try not use an ISO higher than 400.

If you have a focus problem, you will see it here. Phase detect focusing is fast, but not quite as the slower but perfectly accurate contrast detect focusing in live view. Also, when focusing through the viewfinder, there is always the possibility that you will get focus shift as you narrow the aperture, but the lens will always be wide open as you focus. Depth of field increases as you stop down, which usually masks the focus shift.

An autofocus problem, assuming it is not a lens element centering issue - will provide perfectly focused images with live view, and either front or back focus if you focus through the viewfinder.

So before you adjust or fix anything, first see what the lens can do. Lens autofocus performace in phase detect is part hardware and part software - using AF Fine tune only addresses AF performance at two distances and zoom levels. A firmware adjustment will improve autofocus performance over a broader range. If you see an AF problem with more than one lens, then the body is suspect as well.

I recently had an AF issue with a D800. Contrast detect provided critically sharp images with all my lenses. But using Phase Detect all of the images were unusably soft. Even a -20 value in AF fine tune failed to yield accurate focus. A trip to Nikon corrected the issue, and now all lenses were focusing correctly with no AF fine tune dialed in.

This is not the same as focus breathing which describes an entirely different lens behavior. This refers to the internal focus lenses which do not change their length as they focus. In order to focus at their shortest distance without changing size, the designers adjust the focal length to a shorter one. A 180mm macro can be as short as 135 at 1:1. This is known as a varifocal lens. The lens that does change length as it focuses is a parfocal lens.

These articles are helpful:

http://photographylife.com/how-phase-detection-autofocus-works

http://en.wikipedia.org/wiki/Autofocus

http://www.digitalcameraworld.com/2013/12/06/how-live-view-autofocus-works-what-your-cameras-manual-doesnt-tell-you/2/

http://flareout.sawfnews.com/tech-take/phase-difference-vs-contrast-detection-autofocus

RegisG Loc: Mid-Tennessee

I appreciate all the tips and help. I'll be doing these tests this afternoon
I'll do both ways that Gene51 and Naturepics43 outlined and post some results this evening.

Thanks again for all the input and I hope that I don't have to take back for repair.

RegisG

Dlevon Loc: New Jersey

Was the window open? Shooting through glass?