knelso4

Is there a method to decide how much to adjust for front/back focus, or just pick a number, try it, test, repeat?

MT Shooter Loc: Montana

First you need to see if it even NEEDS any adjusting. Then its pretty much trial and error to see how much may be needed. If its focusing right, don't screw with it at all, you'll just be wasting your time.

knelso4

Yes, it does. That is why I'm asking.

47greyfox Loc: on the edge of the Colorado front range

I have the Sigma 100-400 Contemporary and faced the same dilemma last year. I use it on a Canon 6d2 and 7d2. Neither seemed as sharp as I expected. I hooked up the dock and jumped into the deep end. It didn’t take long for me to decide that I wasn’t in my comfort zone, so I got out of the water and called Sigma. A day later, I shipped the lens to NY where Sigma performed an auto focus calibration. Lens was back in my hands shortly thereafter and has been spot on since. And I didn’t get frustrated once.

Strodav Loc: Houston, Tx

The Tap-In tuning table for the Tamron 18-400mm f/3.5-6.3 has 24 entries (8 zoom factors at 3 different distances). The way I check to see if I need to adjust at the first two distances (.45m and 3m) is to set up a test target, like a newspaper or magazine page full of text (images are not as helpful as text), at about a 30 degree angle to the camera and shoot under CONTROLLED CONDITIONS to see if the lens is dead on, back focusing, or front focusing. Make adjustments as needed. Testing at infinity is a bit trickier.

My copy definitely required tuning. After tuning, I have been very happy with the results on my D500 even at 400mm. I'm guessing that those who are not happy with this lens' IQ, have not tested and tuned it, but it's possible they got a bad copy. It's not tack sharp, but you shouldn't expect it to be, but as light and flexible as it is, it's a pretty amazing lens.

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Metis407 Loc: Canada

I did the same with Tamron 18 to 400. Came back very quickly and has been spot on ever since

Pistnbroke Loc: UK

I just give up with this site ...what camera are you using ??? If its a Nikon D850 D500 or 7500 then the setting is easy to do ...the other no so .

Metis407 Loc: Canada

Canon 77d. Not sure my answer deserved your snippy reply!!

Pistnbroke Loc: UK

So it does not have any auto fine focus adjust so you will have two choices . do a fine focus adjust at max focal length 400mm with the tap ins at 0 .store the figure in the camera ( if your camera supports that ) and leave it at that or do all the checks and programme it in.
In my experience the figure can vary wildy through the zoom range and distance so its worth the trouble

knelso4

Canon 90D. I can adjust for wide and tele but that is limited. Using Tap-in console, finished 1.5 and 8 ft, now have to do infinity.

knelso4

I sent it to Tamron to get the tap-in console to work (it had a bad connector) and asked them to check focus. I don't think they did anything.

47greyfox Loc: on the edge of the Colorado front range

So, you shipped the lens along with the console? The tech probably grabbed a tap-in console and everything went back in the box. Was there any kind of invoice that listed what they did? It shouldn’t be this hard..... but with your order number in hand, I suggest a phone call asking Tamron what was done.

Strodav Loc: Houston, Tx

My first Tamron lens was a 150-600mm f/5-6.3 G2, which I bought for use with a D7200 for birding. I was not happy with it at all and after discussions with Tamron, I sent it back to Tamron along with my body for repair if needed and tuning. There was nothing wrong with either and the lens was not much better when I got it back. I thought I had wasted my money. Long story short, I picked up a tap-in, learned how to tune and am now getting excellent results with the G2 on the D7200, a D500 and D850.

FWIW, what I have learned is that Nikon does a very good job of maintaining focus throughout the zoom range, so if they need to be tuned to a camera due to age, tolerances, etc., all you need to do is tune them at one point and you are good to go. Nikon does not sell a "Tap-In" because they don't need to. Tamron doesn't have that kind of QC on all of their lenses and focus can vary with zoom factor, which probably explains one of the differences in price. Tamron needs to sell the Tap-In for tuning, but once tuned they perform very well. I've learned this from 6 Tamron lenses (4 zooms and 2 primes) along with several Nikon and a couple of Sigma lenses. If you are willing to tune, then you can save quite a bit of money buying Tamron or Sigma glass and get excellent IQ. If not, then buy the original manufacturer's glass.

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

Your experience with NIkon lenses is not the same as mine. At different distances, a prime lens can have all three conditioons - front, on target and back focus. With zooms, you can fuggedaboudit. I have several bodies and a dozen lenses. If I were to worry about fine tuning everything it would take me a month to get everything done. So, I make sure that periodically my bodies go to Nikon - once every 18 months or so. When I was actively working, it was every 8-12 months. This ensures that the camera bodies are correct. When I get a new lens I do test shots with it on at least 2 or 3 bodies. If anything is out of whack, the lens goes to the mfgr for focus tuning. Period. The only time I spend with focus tuning is to take some shots, look at them, then pack the lens and send it off if there is a problem. I am fussy about focus, but I am not OCD.

byuaceman Loc: Mesa, AZ

I used this method and it worked great. It is a little bit of trial and error but it does give you a sense of which way to tweak. https://www.youtube.com/watch?v=J3XK4hf-NF0