which lens to buy?

[Greg Beetham]

A couple more to finish.

DSC03800-f11-crop.jpg (168.83 KiB) Viewed 4801 times

f22

DSC03802.jpg (220.38 KiB) Viewed 4801 times

DSC03802-f22-crop.jpg (158.37 KiB) Viewed 4801 times

[agorabasta]

Greg, but you simply cannot have that last image - that's how your diffraction doctor has prescribed

[agorabasta]

OK, now I'm not trying to joke. Please check this link - http://www.deconvolve.net/bialith/Resea ... ckblur.htm and read some more from that site and then maybe some from their links.

The fact is that even diffraction-blurred images may be deconvolved rather efficiently. But without diffraction your chances are even better.

[Greg Beetham]

I had a look at that agorabasta and it seems quite an accomplishment to de-blur something so far out of focus back to something almost acceptable, those blurry modesty patches they put on rude people with no clothes on in news items occasionally might not be as safe now as the puritanical/hypocritical politically correct thought police think they are.
But realistically I think it’s probably only useful to investigation agencies maybe…so far.
Greg

[agorabasta]

We don't have any deconvolution sharpening in our regular commercial raw developers, but you may already try it in RawTherapee.

Basically, the amount of de-blur is only limited by the noise in the image. And you may already sort of use it for some serious work, just have the files developed till non-sharpened tiff's in your regular workflow and put them through RT. It works.

[agorabasta]

Here's the same JPEG crop at f/22 I posted earlier, now put through deconvolution sharpening in RT3. You may try it for yourself, as I really used the image you may find up in this thread.

If not for the JPEG 'noise', it could be made indistinguishable from the f/4 result for most practical uses.

[Greg Beetham]

I definitely looks cleaner and sharper, but it seems to disappear some little bits and pieces also, but pretty good overall I think.
I should re-do a couple of my shots, I stuffed up the exposure and they are full of image degrading noise. I had the F56 on top of a light stand pointing down, I was looking for a ‘flood’ effect without harsh edges, but forgot the WL mode sets the F56 to 24mm zoom, which in turn dramatically lowers the GN, too low for about 7feet and ISO400 at f22 even the f11 shot was underexposed slightly, and didn’t notice until they were on the monitor….after I had put everything away.
Greg

[agorabasta]

I definitely looks cleaner and sharper, but it seems to disappear some little bits and pieces also, but pretty good overall I think.

Well, you see the result of two very lossy compressions.

And then there's still some noise, which is actually the real limiting factor with any type of sharpening and detail restoration. So a viable approach to using very tight apertures for macro work could be stacking a series of exposures to kill the noise and demosaicing artifacts and then apply the deconvolution sharpening. Should work very well for the still objects.

[Greg Beetham]

There is an article from B&H listing the wide angle lenses currently available from most of the manufacturers at the moment. http://www.bhphotovideo.com/indepth/pho ... ns-roundup and another article listing all the manual lenses, http://www.bhphotovideo.com/indepth/pho ... ns-roundup it’s great to see Nikon still make a selection of proper lenses with f-stop selection and MF, also of interest is a list of Carl Zeiss lenses with Nikon, Pentax and Canon fit. Both articles don’t make any attempt to review any of the lenses, it’s just a list of what is currently available.
Greg

[agorabasta]

Returning to the Nex5N DoF issues (most likely the same as a77 issues), I have to say the following -

Focusing at around 3m away, using auto or manual focus, I definitely see much more DoF in front of the focus point rather than behind. At f/2.8 the best focus falls almost at the farthest end of apparent DoF, which is absolutely not normal.
Stopping down further surely extends the DoF, but much slower than expected in the farther part. Stopping down further yet, there's another area of Dof starting to form from infinity to back (to the front, actually).
Then only by f/22 the DoF of my Tamron 28-75 at 35mm looks like it should look in theory. Even at f/16 there's a very pronounced blurred gap starting at about 5m...

So it appears that the problem is not really limited to UWA or any particular lens for that matter. It's a very specific problem with the camera body optics.
Later on I'll check for the distances at which the nasty effect goes totally off, but for now I suspect that it stays there all the way till hyperfocal...

P.S. Frankly - what a bummer... ! No other Nex has such problem, none of my earlier alphas do either. I guess too much 'technological progress' happens much too fast to some company...

[lonewolf16x9]

We don't have any deconvolution sharpening in our regular commercial raw developers, but you may already try it in RawTherapee.

Basically, the amount of de-blur is only limited by the noise in the image. And you may already sort of use it for some serious work, just have the files developed till non-sharpened tiff's in your regular workflow and put them through RT. It works.

Is this the same basic Idea as Topaz In Focus which I've just started using for my Sharpening? Looks interesting...
http://www.topazlabs.com/blog/topaz-inf ... echnology/

[Greg Beetham]

I think there might be some kind of 'plane' issue with the sensor or the filter, maybe even an air gap between the sensor and filter in an area in the middle agorabasta. David said the 16 had a cup shaped field, so I guess with that lens it depends where the plane strikes through the cup, up towards the rim, in the middle or down at the base; and does that vary from lens to lens, camera to camera, and does it vary with focus distance as well.
But all in all if the strange DOF issue exists with other lenses as well then the problem is not just confined to lenses one would think.
Greg

[agorabasta]

Is this the same basic Idea as Topaz In Focus which I've just started using for my Sharpening? Looks interesting...

Basically, yes.

But there are far too many deconvolution algorithms. The problem is that the algorithm should work on a fundamentally reduced data set, and the mathematics for those kinds of problems is not completely developed. But there will be some serious progress quite soon as the commercial products are fast becoming viable.

[agorabasta]

Greg,

I only report my findings with my cameras/lenses. David may see a somewhat different problem, or even more than one problem.
But I'm not going to buy an a77 with the sole purpose of investigating its deficiencies. It would be better to ask the existing users to report their findings. At least, it would be rather easy and straightforward to have a77 checked for the specific problem I described here.

[David Kilpatrick]

Here's something to confuse you further: the A77 may have an issue (firmware v1.04) following startup. Far too often in the set of files I have been processing the first frame after switching on the A77 is seriously out of focus. I've been checking my raw files, to see whether this happens only if I switch on sudddenly and shoot immediately, but that is not the case. I have an unexpectedly high incidence of first frames being defocused, even when the camera has been turned on for a minute or two to allow the GPS to register.

At the most, I have two frames showing focus error before the camera focuses normally, and continues to focus normally. It does not seem to depend on the lens and the error is so great that a landscape at f/10 can be out of focus, even though I am certain focus confirmation was given by the camera before taking the shot. This is not a targeting error, as the entire shot can be out of focus (it's not picking the foreground by mistake). I now need to recover several images from trash, because I have been deleting them without spotting the pattern. Now I know this is happening, I will study each 'shoot' with care.

This has happened with the 16-80mm but also with the 8-16mm Sigma (I thought it was a lens compatibility issue). I do not have the AF/MF button set to toggle and it seems unlikely the camera could be accidentally set to MF. Also, the point of focus does not indicate that either.

This could also have happened with the test A77 I briefly used in London and would explain some of the poor focus results.

David