One more 12-24 question (more crop samples)
I appreciate all of the help so far, so I hope you will excuse me for requesting the review of another image (actually a crop). Per my last post, I got a 12-24 yesterday and did a couple of quick snaps. It's raining today, so I can't venture out to try any more.
I've done more looking at the 12mm pics and I guess I'm still confused about what you would characterize as CA. There is one area in the photograph I posted earlier, and the same general area (both locationaly and in the frame itself) from a different photo and different vantage point that I am still curious about.
Please have a look at the crop linked below (sorry, I've had trouble getting a "zoom-in" crop, so this is about the best I can do right now). Look within the fence and you'll see sets of small, horizontal, black bars covering up some of the areas of the pic where the actual black vertical bars of the fence should be. (This photo from where I took this crop has actually less of this than my other test image) Is this also CA like in the trees of my prior pic? If not, then any ideas what is happening here?
Here's the link: http://www.pbase.com/gc/image/56473726
The prior picture I have out there, if zoomed in enough, has these small horizontal bars all over the place to the right of the blue slide.
I appreciate everyone's patience. I spent a lot of money on this lens and I want to make sure I fully evaluate this thing and understand what is going on (or not going on) with it. Then I can decide whether it works as advertisted, to "live with it", try another copy, or just return it. If the problems are solely my technique, then I'll have to rethink things. If you can't successfully handhold the lens at the wider focal lengths, in adequate light, and get decent pictures, then I'll be disappointed.
Thanks again for the help!
#1. "RE: One more 12-24 question" | In response to Reply # 0walkerr Nikonian since 05th May 2002Fri 24-Feb-06 08:14 PM
It looks like CA to me. If you have Nikon Capture, try shooting in RAW and enabling "color aberration control". There are no settings to mess with, and it works very well. If you don't have Capture or are shooting in jpeg mode, there are some equivalent functions in photo editing software packages that will reduce its effects, they're just not quite as simple as Capture.
#2. "RE: One more 12-24 question" | In response to Reply # 1Fri 24-Feb-06 08:41 PM
Thanks. The pic I pulled this crop from was shot in RAW. The crop was from the center of the frame. In the same pic, in the upper left of the frame, there as purple fringing (my previous definition of CA) and when the color aberration control is activated, the purple fringing goes away, yet it has zero effect on these small black lines. That's why I am questioning if they are CA.
I've put two more crops out there. One from a 15mm image: http://www.pbase.com/gc/image/56476049 and one from a 24mm image: http://www.pbase.com/gc/image/56476160.
Both these, like the others was shot in RAW. The 24mm looks clean.
Again, the CA control in Nikon Capture has no effect on this area of the picture when there are the horizontal black bars.
#3. "RE: One more 12-24 question" | In response to Reply # 2delaneyb Charter MemberFri 24-Feb-06 09:24 PM
Its not the lens - this is moire. Its a characteristic of the digital sensor....
Where fine linear detail is present the image can get an interference pattern like ripples as it crosses the grid pattern on the digital sensor. Its why there is a 'softening' filter on the sensor and why we have to sharpen images.
I suspect you are seeing it because the fence is small inough with the wide angle to cause this effect. Do you have a D70? its meant to be a bit more prone.
It usually only shows up in 100% crops and shouldn't be visible in a normal image.
Hope this helps.
Nikonian in London (Tower Bridge area) UK
Brendan Delaney Photography
Visit my Nikonians gallery.
#4. "RE: One more 12-24 question" | In response to Reply # 3Fri 24-Feb-06 10:00 PM
I have the D50.
Well, hopefully I can venture out on Sunday (supposed to rain tomorrow too ) and try again with the lens. I'll not include a black fence this time!
I hope I can get some better results.
#5. "RE: One more 12-24 question" | In response to Reply # 4walkerr Nikonian since 05th May 2002Fri 24-Feb-06 11:19 PM
Brendan is right regarding the moire. One other suggestion - don't forget to try some actual prints before you pass judgment on the lens. Viewing at 100% will give you false impressions about the results you'll actually get.