tonyjag Loc: Bolton, Ma.

This a continuation from 2 other threads:
https://www.uglyhedgehog.com/t-602554-1.html#10396422
https://www.uglyhedgehog.com/t-494368-1.html
I did not have good results with a 70-210 F/4 lens and Tap-In Console, but Hunt's took it back in exchange for a 18-400 lens. This post documents how that worked out...in short, not perfect, but very well and, with 24 unique focus corrections, it is far superior to the Nikon Auto-AF Fine Tuning, which only handles one per lens. But Nikon Auto-AF Fine Tuning provided a repeatable mechanism for measuring the focus front/back corrections, as described in the other threads. I used the same procedure with the 18-400.

First, I connected the Tap-In to the lens and did a firmware update to Version2. Before Tap-In, that would have meant sending the lens to Tamron in NY. Then, I brought up the Tap-In screen for focus adjustment, which has places to enter values for 3 different zooms at 3 different ranges.. see picture.

Next, i set aside the Tap-In and did a series of measurements using Nikon D7500 Auto-AF Fine Tuning as detailed in the other thread on the 70-210. This process involved about 100 different measurements and took hours. I set up my tripod at 1.5', 8' and 52' (for infinity) and did all 8 zoom measurements at each range before moving it. That gave me 24 values to enter. Next, i attached the Tap-In to the lens and applied them as shown in the picture.

To check how well the corrections worked, i repeated a few measurements for each of the 24 cases, resulting in the "A" values hand-written on the picture with various doodles. The result was overall very good, mostly ranging from -2 to +2, but there were two (of 24) outliers at -6 and +4 (circled in black) that stubbornly did not change at all.

I also computed a Delta to quantify the change, handwritten in the picture. Adding up all of the deltas, the net improvement was +35. It is also shown by rows and by zoom. Circled in green are the best improvements, between +5 and +10. Only one result - the worst - had a Delta of -3. Most were between -2 and +2. Of the 24 cases, 10 improved (some dramatically!), 7 didn't change, and 7 were degraded, but not by much.

Overall, a great improvement! I plan to use it in Antarctica in December, with the D7500 Auto AF Fine tune either off or set to zero. It will work equally well in my back-up D5300. Any comments, like your experience with the 18-400 and Tap-In, or questions will be appreciated.

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Strodav Loc: Houston, Tx

I went through the same stuff with my Tamron 150-600mm f/5-6.3 G2, even sent it back to Tamron with my body to have them tuned together, and it was still not sharp when I got it back. Finally bit the bullet and learned how to tune. Once I was done, I started getting excellent results, which gave me confidence to buy other Tamron glass including the 18-400mm f/3.5-6.3, and now Sigma glass.

What I believe I have learned is that Nikon quality control keep a zoom lens focus consistent though the whole zoom range, so all you have to do is tune one point using AF-fine tune and it will be sharp through the whole range. Tamron and Sigma glass are inherently sharp, at least in the center, but focus varies through the zoom range, but you can walk it in with the tap-in (USB-dock). So IF you are willing to tune Tamron and Sigma glass, you can save yourself some money and still get excellent results. IF you are not willing to tune, buy Nikon glass.

tonyjag Loc: Bolton, Ma.

I agree. I only have one Nikon Zoom, a 16-85, but it's AF Fine Tune correction is fairly consistent:
-2 at 16mm, 2',
-6 at 35mm, 4',
-4 at 50mm, 8', and
-3 at 85mm, 11'
So i use -3. The attachment shows a summary of lenses. The big Sigma is also pretty good. I plan to use a +3 correction at 300-500mm.

BTW, my original post has an error that i am already not allowed to edit. In the second paragraph, it should say 8 (not 3) zooms.

Attached file:
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olemikey Loc: 6 mile creek, Spacecoast Florida

Nice work, good effort and it paid off!!

roset

Question: what is a tap in? I hate to admit this, but what are y’all talking about?

Strodav Loc: Houston, Tx

It's all about tuning lenses for optimal sharpness on your camera body. Tamron has a device called the Tap-In that allows you to hook your lens up to your computer to update firmware, fine tune AF at different zoom factors and distances (only distances in the case of primes), and customize how AF works in the lens. Sigma has a similar device called USB-Doc. Nikon does not have an equivalent mainly because, IMHO, they do a better job of quality control by maintaining focus throughout the whole zoom range, but sometimes a Nikon lens will benefit from tuning at one point to account for variation in tolerances between a body and a lens, so Nikon provides for AF-Fine Tune in their mid to upper end dslr bodies. Hope this helps.

tonyjag Loc: Bolton, Ma.

Good summary. I would just add that only the newest Tamron and Sigma lenses are compatible with Tap-In or USB Dock. None of my 3 Sigma lenses would work with USB Dock. There is a list of compatible lenses on each website. Also, AFAIK they are only available for Nikon and Canon mounts, which of course need different devices. But they only cost $60 and software for your Mac or PC is free.

tonyjag Loc: Bolton, Ma.

Here is my latest lens summary. I am considering replacing the Nikon 16-85 with a 16-80 and will begin a new thread on that.

(Download)