24-70 VR - Nikon vs Tamron

<p>Eric, I was not lying about the 24-70 Nikkor I was offered at my local Calumet. The thing was apparently brand new and seized almost solid at 50mm. I obviously didn't want to force it with full arm strength, thinking it was a demo lens, but when I asked to see another sample I was told it was the only one they had in stock and that it would have been the lens I walked away with had I stupidly bought it.</p>

<p>Do an internet search for Nikon zoom ring problem. You guys might have just been lucky, or maybe they tried to fob all the bad ones off in the UK or Europe. Most of the posts seem to go back a few years, but this was exactly the time I was shopping for a mid-range zoom. Anyhow. Glad I bought the Tamron 28-75mm. I've taken thousands of shots with it over the last 5 or so years, and the only sign of wear is shininess of the rubber zoom grip.</p>

<p>Demo lenses are sometimes pretty banged up. I noticed that at Heathrow airport in an electronics store a lot of the cameras showed substantial mechanical damage, some refused to function suggesting some electrical damage as well (one Sony camera's EVF image was vibrating in a pathological way). I would not make judgments of a lens' quality based on a demo lens.</p>

I can say that my new 24-70mm f/2.8 vr has a very smooth zoom function, albeit not light. It is smooth enough to use for video.

<p>As Rodeo Joe mentioned the Tamron 24-70 2.8 is one of the few lenses that I haven't needed to apply AF fine tuning,whereas I have had to do some slight focus tuning with all my Nikon's.</p>

<p><em>dr:</em><br>

<em>As Rodeo Joe mentioned the Tamron 24-70 2.8 is one of the few lenses that I haven't needed to apply AF fine tuning,whereas I have had to do some slight focus tuning with all my Nikon's.</em><br>

I am not sure why this means a problem with Nikkor lenses? AF fine tune is quite a normal thing to do with nothing to do with lens quality. It could be just a matter of luck if you didn't need to do it for a lens.<em><br /></em></p>

<p>I'm surprised about how positive people are about the Tamron. I tried it out, and I didn't like it. Yes, it feels strong, sturdy and durable. "tactile" wise it feels better than the Nikon. but:<br>

- The VC sucks. It lags, jumps around with a lot of "jitter" when I move it quickly from left to right (and vice versa), and doesn't transition at all from still to moving, in fact it jumps from still to full motion. I noticed this with all Tamron lenses that have VC.<br>

- The optics are soft. They are also soft. And did I mention soft?<br>

- vignetting. Plenty of it.<br>

- AF, not that accurate, slow, and a lot of hunting<br>

I used to have the 28-75, which was really good actually. But all VC lenses of Tamron were soft, slow and the VC was so annoying I switched it off all the time. I actually tried about 5 samples of the 24-70 VC model. All behaved exactly the same (hat off for consistency there). I concluded that the 24-70 is not even close to either the Nikon or Canon version of the 24-70 (obviously without VC/VR/IS).<br>

The only Tamron lens I'm currently am considering is the 15-30, because that too has raving reviews. But I think I'll be comparing it with the 14-24 Nikon lens side by side when I'm in the shop...</p>

 

DR:

 

Focus fine tuning need is a function of the out-of-whackness of both the lens and the camera body. So the fact a

particular lens doesn't need fine tuning on a particular body says nothing specific about the lens. All it says is you have a

body which so happen to be out of whack in such a way as to exactly cancel out the out-of-whackness of that particular

lens.

 

I had 3 lenses which I tried on two different D810 bodies and one D750 body. Each lens needed a different amount of focus fine tuning on each of the three bodies.

 

Put the lens on a different body of the same model, chances are it would now need some focus fine tune.

<p>I find that in the past two years the (Nikon) lenses and camera bodies that I've bought new have needed very little fine tuning which suggests that Nikon is getting manufacturing in tighter control or moving towards designs which are more tolerant. I think there was a lot of problems with AF calibration in products made in 2011-2 but that seems to be in the past now, or at least I've not run into serious problems recently. Of course I can't speak for other people's experiences.</p>

My experience is 70-200f/2.8 VR-2 needs a lot of fine tuning. I had two examples. The first one needed more fine tuning

at 200mm f/2.8 than the D810 could provide. The second one needed +16 at 200mm f/2.8, +8 at 135mm f/2.8, and +2

at 70mm f/2.8.

 

The fact that the lens require substantially different amount of tuning at different focal lengths is annoying. I strongly

suggest to Nikon that if Nikon can't ensure a zoom lens would back or front focus by a similar amount through its entire

focal range, then let the user define 3 fine tune values at 3 specific focal lengths and have the camera interpolate in

between.

<blockquote>

<p>if Nikon can't ensure a zoom lens would back or front focus by a similar amount through its entire focal range, then let the user define 3 fine tune values at 3 specific focal lengths and have the camera interpolate in between.</p>

</blockquote>

<p>I think that is a good point. For zooms, we may even need more than 3 different points (different focal lengths) for AF fine tune, especially when the zoom range is large. Unfortunately, AF fine tune is now part of life as some of us do plenty of pixel peeping. When my 200-400mm/f4 AF-S VR was new (back in 2006), I didn't need any AF fine tune when that feature became available along with my D300 in 2007. However, after a number of years of usage, that lens gradually needs some AF fine tune to product excellent results.</p>

<p>Chuck, what distances did you use for testing the focus fine tune? In my experience using close distances for fine tuning (as suggested by some target manufacturers) usually leads to poor results at long distances. My 70-200/2.8 II has needed negligible fine tuning on any of the cameras that I've used it with which is quite a few, and it's consistent across its focal range on each camera, in fact it's been the most consistent of all my lenses in that respect. I typically use a target distance of 30-50 times the focal length for testing the focus accuracy.</p>

<p>The problem with giving users more freedom of parametrisation of the focus fine tuning is that it can quickly lead to a very complex mess. Wavelength of light, distance to subject, focal length, and aperture selected and any combination of those parameters would ideally be given a separate fine tune value for each lens. In my opinion it's better to design the lenses so that minimal fine tuning is needed and variation across parameters is small. If there is large variation Nikon should be able to solve those problems in service. The problem is that image resolution has dramatically increased in the last 10 years which has lead to the need for the AF system to be much more accurate, and the AF system has only gradually been catching up (with the increased resolution). </p>

I initially used infinity focus on buildings and window frames more than 3000 feet away to test the focus on the 70-200. I

later got essentially the same results using Michael Tapes' Lensalign G3 at about 20-25 feet.

<p>Ok. I would have Nikon authorized service have a look at the lens, with an explanation of your findings.</p>

<p><em>"In my experience using close distances for fine tuning (as suggested by some target manufacturers) usually leads to poor results at long distances."</em><br /> <br /> Exactly. I remember I started to noticed this back with the D300 + 17-55/2.8... It was quite difficult to set fine focus calibration at very close distances; a very little improvement (if any) lend to a bad performance at longer distances.<br /> At the end, I think I settled the focus at 2-3 meters; all my pics were plenty sharp.<br /> <br /> I think a bit of pixel peeping is fine, but I wonder if sometimes things are taken to the extreme.</p>