Tamron 14mm f2.8

[David Kilpatrick]

This is a very expensive lens - £800 or so in the UK - and when I first had the Dynax 7D, I bought one at a much reduced price new - only £245 from Mifsud. It seems Tamron wanted to clear their inventory of this lens in non-D Minolta AF fit. It was an excellent lens but hardly got any use, as the 11-18mm Tamron/KM lens arrived just a few weeks later. With no idea that full frame would arrive within three years, I sold the Tamron for not much more than a paid for it (again, thinking that the lens was probably discontinued, and would never again be seen for sale at £800).

Of course, this was a mistake! Although the lens had softness even on the 7D at the edges, we did not have proper CA correction tools in Camera Raw and I can see by looking back at the images that a new conversion could be MUCH sharper than the ones I did in September 2005. Also, now that I use both the A700 and A900, I realise the value of f2.8. If your lens is f2.8, it switches on the f2.8 centre AF sensor which does not operate at all if the camera detects a lens less than f2.8. This sensor is FAR more accurate than all the rest, especially with wide-angles (it is nothing like as important with long lenses). This is why the CZ range for Sony will be 16-35mm f2.8, 24-70mm f2.8 at the wide to standard end - and why it would be good to have had a 17-55mm f2.8 for APS-C. And with the A900, I now see how the Tamron 14mm could have been a perfect addition to the outfit. Instead, I have bought a Sigma 12-24mm which may well be sharper but can never use the f2.8 AF sensor.

Problems handling distortion with the 14mm are best solved by rigorous attention to lining up the camera, or corrected later using Photoshop.

Here are two examples of camera lining-up technique with the 14mm:





For the first one, the ceiling of Santa Maria de Bergamo, the lining-up was done using the tiled floor. The camera was placed on its back (the 7D lies flat, which is a useful feature for any camera) after setting the aperture-priority exposure and using 10 second self timer. It was placed exactly on the centre lines formed by the floor tiles, and lined up with them by eye, before moving quickly away from the camera in time for it to fire. I nearly always use the features of architecture to get my camera precisely positioned - I will line up the centre column of a door with the centre window at the other end of a church, for example, or move so that symmetrical features in a building are precisely mirrored in the viewfinder.

This was the basic technique for the second shot, the cathedral of Como. I stood on the line formed by the square's paving which led precisely to the centre of the door, and aimed the camera up taking real care not to angle the horizon. I have just bought an L-type screen for the A900, I never got round to having one fitted in the D7D or the A700. Shirley always had one in her 7000 and 7xi, and me in my 9000 and 9xi. I don't have one in my Dynax 7 film body but it is very unlikely to see regular use again. We really should get the A700 fitted with an L screen.

Here is an example of 2005 Photoshop re-alignment of a 14mm shot which, because of the space available, was bound to be angled upwards and leaning all over the place:



This adjustment was done without using the new Distort>Lens Correction filter/module which is present in CS3/CS4, and a better conversion is now possible. Also, I was not aware in 2005 how much the red channel gain affected noise in sky blues - and I accepted ACR's auto, camera settings or daylight WB without questioning them. While the result is pleasantly warm, it is also a bit 'strong' in density and doesn't reflect the real colour of the light or the sky. Making a new conversion, +50 Red/Cyan CA correction could be applied (totally removing the slight visible CA) along with highlight defringe, and the WB lowered to 4600K with 0 magenta tint. The result is not as attractive and looks 'colder' but it's more accurate, and the sky is transformed from being noisy to being clean.



http://www.pbase.com/davidkilpatrick/image/107487464 - link for full size image, feel free to download it and experiment with Photoshop corrections for the perspective.

Here is a version using the latest Photoshop tools and a further fine tuning to the ACR conversion at 5000K but using the new Adobe Standard camera profile in place of ACR 4.4 profile (the limit of warming up the image, before sky noise became obtrusive):



You can probably see the benefits of the new tools in creating a more natural looking perspective correction, with 4% barrel distortion also removed. The sky is rendered brighter with the new ACR 5.2 camera profile, and less magenta, so the shift to warming up the scene in general does not result in a purple-blue sky, it remains a clear blue.

NB: the Tamron consistently reported 15mm as its focal length not 14mm.

David

[PhotoTraveler]

Interesting comments on the processing.

I passed on the Tamron, it was just too expensive and too big to get that wide angle, especially being 3rd party, old. With the A900 out, I would expect Sony to bring some FF prime lenses in the 14mm to 24mm range. They never had a 14mm, which might be a good idea, but I'd like to see them make any such lenses an F4. Something that keeps the size and weight down so someone could carry it with the expected 4/24-105 as a carry along for when a wide angle need comes up. Even a 4/18 or 4/16 if it could be not much bigger than the 2.8/20 would be good. I just don't want to lug a boat anchor around for what might come up.

Your shots definitely show why software can't replaced TS lenses. Loose a lot of photo, and the results look fairly wonk. Just the way the tower gets so pointy, or how it's corners no longer align with the corner of the building in front of it, they now diverge as you go up.

I really hope Sony has been listening and has some news by PMA. With Sony not having anything into the Tele/PJ/Sports market, but having a camera that is right up the isle of independent Pros, Landscapers and so forth. A line of TS would do them great. And even do something extreme like a F4 PC zoom at the super wide angle range could change their fortunes a lot. They aren't going to knock into the markets that Canon owns and Nikon tries to keep up with Canon in. Instead just go and dominate the markets Canon and Nikon don't actively own/push hard.

[01af]

Your shots definitely show why software can't replace T/S lenses.

They do!?

Lose a lot of photo, and the results look fairly wonky. Just the way the tower gets so pointy, or how its corners no longer align with the corner of the building in front of it, they now diverge as you go up.

It would look just the same way when shot with a shift lens. The perspective comes from the point of view, not from straightening diverging verticals. Of course, a real shift lens would make better use of the sensor's real estate ... but the weird look would be basically the same.

The only thing you cannot mimick in post-processing is a tilted lens where the plane of focus isn't parallel to the image plane. But that wouldn't help capturing high buildings from a low point at a short distance. Here, a shift lens would have been required---and that can be properly substituted in post-processing.

-- Olaf

[Dr. Harout]

Sorry Olaf, but I agree with PhotoTraveler. I would prefere a Tilt-Shift (PC or whatever it might be called) to a PP stuff. If you might correct some instances with PP, surely you can't do that on close subjects when performing extensive perspective control.

[01af]

I would prefer a Tilt-Shift [lens] [...] to a PP stuff.

So would I. In fact, I sincerely hope that Sony (or Zeiss) will bring a T/S lens---or better yet, a whole range of T/S lenses---for Alpha mount sooner rather than later.

If you might correct some instances with PP, surely you can't do that on close subjects when performing extensive perspective control.

A T/S lens has two separate features: tilting, and shifting. With a shift lens, you can't do anything that you couldn't do in post processing just as well ... except that in post processing you'll always lose some of the pixels near the frame's edges. With a tilt lens however, there is no way to simulate the effect after the fact at post-processing time. So in a T/S lens, the tilt feature is the important one; the shift feature is very nice to have but not essential.

-- Olaf

[Dr. Harout]

Exactly, Olaf.
Sony should really read this, just in one little thread 3 persons are ready buyers...

[Dr. Harout]

I have repeatedly posted this T/S message for months if not years...

-Sonolta

I wasn't counting myself
But on the other hand, make it 4

[PhotoTraveler]

I've polluted every possible thing I could with my wants since the KM days. It's something I'm willing to go to the point of overly-annoying about. And it's pretty clear there is a lot of such people doing the same. I think the biggest issue is when people say they aren't needed, that just fuels folks more.

If we could just get a response from Sony, either about them in the works, or that they won't be making any such lenses that would let us move on. While I can understand Companies not wanting to give road maps, and I often agree with the logic of not doing them. I think Sony needs to do a road map on lenses with some pretty good details, at least to the level pentax does.