24-70mm f/2.8 is a particular set of numbers that you want packed in one lenses on you camera. It is the absolute base of any type of photography. No wonder Nikon puts such a high price on it. At least in my experience, this range is what I use the most. Unfortunately, you don’t have many choices. Right now you can only get decent performance form Tamron 24-70 f/2.8 or Nikon 24-70 f/2.8. Tokina just came out their own version, so I have no idea how good it is and Sigma is not really there in terms of quality.
Due to the fact that Nikon version of the lenses is damn expensive, I have decided to get the Tamron 24-70 f/2.8 VC, some time ago for around 1000 Euro. I should mention that back then I was not owning an FX camera, but a DX, the Nikon D7100. I was thinking in perspective, slowly building a fleet of lenses for my future FX. Right now I use it on a Nikon D810. Tamron looked amazing on paper and the early reviews were stellar. I mean, it has stabilization for this focal range. The hype culminated with the DxOMark who gave an impressive rating to the lenses sharpness. Thus, I made what I thought it is an educated decision.
When I bought the lenses I was not very knowledgeable. The lenses felt OK on D7100. Not being a very good range of focals for the DX sensor I didn’t really used them so much for about an year or so, except for our holiday in La Palma. After La Palma I have started using them more extensively mostly because I started to appreciate a lot more what they are. And then, I have started noticing a lot of problems.
1. Problem number one was sharpness, which was all over the place. Particularly, the left half of the lenses was less sharp then the other half at any aperture. I did multiple experiments and I have concluded that the lenses are not centered
2. The second issue was VR. Stabilization was working but my images had double edges and ghosting. I tried without VR and the images were tack sharp. Now, I know that the Tamron VR needs to “warm” for 1 second, but this was worse. During winter, under 5 degrees, images always had ghosts, with or without VR warming. On the DX this sucks because due to the high sensor’s noise levels, VR really helps with keeping the ISO low. On the D810 I don’t care so much about VR since I can use images up to ISO 8000 without any problem.
So, I sent the lenses to Tamron to fix them. They’ve changed the entire frontal element and calibrated the stabilization. Now I can actually use stabilization only that if the temperatures are low, the VR still needs 1 sec of warming. But at least they work properly after that. Also, the lenses are now incredibly sharp which I really love. Thus, the problem was solved.
3. But wait! There is one issue that I always had with these lenses and that is the fact the in certain conditions I get overexposed images. I never knew why so I was always shooting compensated with (-1) – (- 2/3) stops and always checking each photo on the lcd which is annoying. I never understood why until now, one year later since I have fixed the above issues.
This morning I was searching if any other people have this issue and I literally found too much information. Apparently, many of the copies have a miscalibrated focus lever with Nikon. To be more precise, in my particular case, even if I change the aperture form the camera, in the lenses it stays the same until like f/5.6. The camera thinks that the aperture is changing and it is adjusting the settings accordingly. The images get brighter and brighter until full blown because the lenses are lazy. That means also that at f/5.6 I am still shooting at f/2.8. I understood finally the issue with having people out of focus at events when shooting at f/5.6 although I felt like they should have been in focus. I have tested this a few times, on manual mode. I shot with the same ISO, same exposure, modifying only the aperture in 1/3 steps. The histogram is exactly the same until F/5.6. After that, the images start getting darker which means that only after f/5.6 the diaphragm starts closing. I haven’t tested yet the consistency of this habit. In any case, it is a defect and I am sending the lenses back to service to have the problem fixed.
(the featured portrait from a Gothia Innovation session is shot at 70mm, f/8 but you might notice from the background blur level that it is more like f/5.6)
Giving the amount of issues I had, together with a lot of other people, it appears to me that the low price of the lenses compared with the Nikon ones was due to the fact that Tamron hasn’t used much budget for quality control. At least they’ve stipulated 6 years of warranty for the lenses, which saves my ass form a possible very poor investment. Sending the lenses for service is not a big deal and I really hope that I can get this lenses in shape in the end. I like them and I really need them.
I have done a little workaround to be able to use the lenses for the holidays. I will have to create a more solid solution and the lenses still need to be sent to service, but for now rolled paper duct tape works. I am sure it is not properly calibrated but at least I get well-exposed images. That starting aperture seems to be around f/2.8 after testing for a bit. The exposure for the images looks to be right.