ron_togger

<p>OK, I think we're getting somewhere.<br>

I just tried opening the NEF directly from photoshop. It seems that after heavy posterisation, a very tiny difference occurs between the original 14-to-16-bit and the up sampled 8-to-16 bit. Too tiny a difference to say "wow, this is clearly superior", but a difference nonetheless - confirmed in the histogram.<br>

View NX continues to produce identical results. This would suggest my earlier notion that View NX cuts the data before exporting it...</p>

<p>..erm btw thanks for your comments Tim, actually I am interested in beautiful images. Which is why I want to ensure I understand my equipment and software as thoroughly as possible. I am not using an 8-bit video display, and I'm not out to boast about my equipment.<br /> What I will say is that since I do not have the luxury of owning a darkroom or a large format film camera any more, I am trying my best to yield the best result in B&W photography using digital as I possibly can. These may well be "minute piece of technology" but actually, I do give a sh*t about it - if that's OK with you.</p>

<p>Greg, Andrew thanks for your comments - that is exactly my point. Both files are up-sampled to the same 16-bit photoshop space. If I paint a gradient at this point and start playing with it, the *painted gradient part* of the image is obviously smoother than the same process repeated within an 8-bit space. I can see the superior 16-bit result in line with my expectations and the difference is obvious.</p>

<p>BUT... what I don't get is the actual captured photo itself.</p>

<p>Forgetting filters for a moment, if I take an 8-bit photo and convert to 16-bit, next take a 14-bit photo and convert to 16-bit (which is effectively what I did in the steps above), would it be reasonable to expect the photo itself to hold more data/subtle tones "hidden" within the image? If I then applied the same extreme posterization side by side, to the point where both images are pushed to reveal banding and grain, should the converted 14-bit version not be at least slightly better than the one originating from an up-sampled 8-bit? In other words, if the camera originally "sees" and records 14 bits worth of tonal variation, should the resulting high-bit TIFF not be visibly superior to an up-sampled 8-bit, following all the editing?</p>

<p>I cannot see any difference: it is as though both sets of outputs (the 8 and the 16 bit TIFF) contain identical amount of actual image data. The "16-bit" TIFF which I am outputting from Nikon simply appears to have 6 bits chopped off, then 8 bits of extemporaneous data appended to it. Hence, when both are edited side by side in 16-bit space, there is zero difference. This would seem to indicate that somehow the RAW data is internally clipped to 8-bits before it even "leaves" the Nikon domain, regardless of which TIFF bit rate you ultimately choose.</p>

<p>As I said originally, maybe I'm missing something here. It's not gonna ruin my sleep but if I'm right, then folks have been exporting 8-bit images to photoshop all along, mistakenly assuming they are "high-bit" when in fact, the only "high-bit" elements are Photoshop-generated artefacts like gradients and effect filters - NOT the actual images you start off with.</p>

<p>Please prove me wrong...</p>

<p>...so if anyone wants to have a little investigative fun, try the following.</p>

<p>1) Open up a NEF file in Nikon View NX. Preferably with light pastel shades across wide areas.<br>

2) Export the file as 8-bit TIFF from View NX.<br>

3) Then export the file as a 16-bit TIFF from View NX.<br>

4) Open the 16 bit TIFF in photoshop.<br>

5) Open the 8 bit TIFF in photoshop.<br>

6) Apply your choice of posterisation filters (comment 5, as per Andrew's suggestion) identically to both files. At this stage, there are obvious visible differences. So far so good. 16-bit looks better than 8-bit.<br>

7) Close files without saving.<br>

8) Open both again, the 8-bit and the 16-bit<br>

9) Now, interpolate the 8-bit upward, by cutting and pasting it into a 16-bit window of the same dimensions so you end up with two identically sized 16-bit versions of the same image, one being the original 16 bit, the other an interpolated 8-bit<br>

10) Apply the same choice of posterizing filters.</p>

<p>Is there any difference between the two? Remember, one is meant to be the 14bit interpolated to 16 bit, the other only an 8-bit interpolated into 16 bit.</p>

 

<p>Many thanks for the responses guys. Tim & Andrew, apologies if I've overcomplicated the question. What I'm trying to get at, is whether a supposed 14-bit raw file I'm opening up in Photoshop is, in fact 14-bit upped to 16, as I see no difference in results between the "upwardly interpolated 14-bit" and "upwardly interpolated 8-bit" files. (Hence my experiment: opening the original straight off as 16 bit, and opening an 8-bit version of the original, then interpolating it to 16bit). It's almost as if the original 14-bit data only really exists in the Nikon proprietary domain, (ie. View NX), but gets chopped as soon as you export it, regardless of whether you're saving it out to 8-bit, or a 16-Bit TIFF. How else would the filters behave identically on both?</p>

<p>sorry... I forgot to add that I deliberately chose images with very light colours and applied extremely heavy level editing to deliberately darken light shades in order to force the banding and other visible artefacts. Some edits DID indeed, produce visibly reduced banding on the 16 bit. I thought I'd solved the puzzle....however...<br>

...I then tried one final test: Create an empty 16 bit document, copy and paste the unedited 8 bit image directly into it, keeping the original 16-bit image open as well. I then applied exactly the same processes to both files. Guess what. Both the "original 16-bit" and the up-sampled 8-to-16 bit files behaved exactly the same when processed using heavy filtration. Unlike the first attempt which eventually produced some subtle differences, this did not. I'm completely lost on this one.</p>

<p>Thanks for the response. It's a puzzle to me. The D3 capture was in Adobe RGB 14/bit uncompressed. Perhaps I am trying the wrong level filters to test these or the differences are too subtle for my iMac monitor...</p>

<p>I cannot get my head around this.<br>

Having exported the same 14 bit NEF Nikon image, firstly as 8bit TIFF, then a 16 bit TIFF (both uncompressed), I applied identical extreme level adjustments to both images. Surprisingly, I cannot see ANY difference in final image quality between the two. Both 8 & 16 bit images look the same, with the same artefacts like gradient banding.<br>

Logic dictates that raw 14-bit files saved out to 16bit should retain more fine tones compared with a "clipped" 8-bit. Applying photoshop tools like airbrush and grad fills makes an obvious difference - the 16 bit file is much finer, but this only applies to photoshop-rendered objects and not the original photo. It almost seems like the 14bit RAW is in fact only 8 bit.<br>

Am I missing a major trick here?</p>

<p>Equipment used:<br>

Nikon D5100 in RAW mode / View NX2 to convert / Photoshop CS5 to edit. Also used a D3 in RAW mode. Same results.</p>

<p>Any comments welcome.</p>

<p>Hi, just bought a cheap 110cm reflector disc off the 'bay for occasional portrait/studio work. It's a standard "5-in-1" pack. I'm generally quite pleased with it - given its bargain price it appears reasonably taut and the reflector material seems fairly hard wearing...<br>

...however, when i try using it as a diffuser, the light source comes through as a cross pattern (or "starburst") effect which is also obvious in reflections on glass surfaces, eyes, etc. Is this a common feature of such diffusers or do the more expensive ones diffuse light more evenly?<br>

<img src="http://ardentcreative.co.uk/DiscDiffuserFabric.jpg" alt="" /></p>

 

<p>...I was also thinking there may be circumstances where a smaller but comparatively "denser" 5200 sensor may actually yield better practical results, the obvious example being macro photography where lens magnification and working distance limitations may be compensated by a higher pixel density bringing more detail to objects which wouldn't fill an FX frame anyway...</p>

<p>Now I know this is neither here nor there in terms of practical photography but...<br>

..with a higher pixel density at a DX size, does the D5200 not provide a potentially more challenging test for lenses compared with a D800 (at least in the DX area)? Since the D800/E, critical sharpness tests have been based on that camera, but if you think about it, the D5200 is actually higher res within DX and would presumably show more detail in that portion of the image. Of course, this is not taking into account other factors like noise, colour depth and obvious advantage of FX. Just pure pixel-per-square-centimeter resolution...</p>

<p>Ron</p>

<p>I also have the 180 ED AIS, and must say, it is one of my favourite lenses - crisp and sharp from 2.8 onwards - plenty of detail and biting contrast from D3 all the way to D800. I've never used the AF version but by most accounts it sounds similar if not slightly better optically - certainly capable of producing better results than the examples above. I'm a huge fan of the 180, in my opinion, it is one of the finest lenses Nikon ever made and certainly has a character that is hard to define using MTF charts and other pixel-counting tests... Just my two cents...</p>

<p>I agree with the above - there are a few laws of physics I would like to repeal...</p>

My Nikon D5100 offers 16mpx across a 23.6 x 15.6mm area, 4828 x 3264.

...If the 5100's sensor had the remaining 12.4 mm added to the width, and 8.4mm to the height to become a full frame 36x24mm, the resolution would be roughly 36mpx, - as per the D800, right?

<p>Now, as we're already reaching 24mpx on DX cameras such as the D3200 and D5200, an FX version of that would be a whopping 56mpx...</p>

 

<p>...given that resolving power of most lenses is already called into question on the D800, I wonder if there are lenses that would (in theory at least) match the 56mpx resolution, or would we effectively come to practical limit of the FX format...</p>

<p>Hmm interesting. I tried it again as per Mike's suggestion. Curiously, the green dot does light up indicating focus in the viewfinder, (but results are still out of focus). I guess the rangefinder feature is not reading directly off the sensor...However the LV technique worked flawlessly - extremely useful feature if a little power-hungry.</p>

<p>Hi guys - can anyone enlighten me...<br>

Yesterday I tried to manually focus an 85/1.4D on a D5100 and despite sharpness in the viewfinder, the results (also shot at 1.4) were way out of focus. I had to compensate the distance manually to get a sharp result - but then it was out of focus in the viewfinder.<br>

Could it be that the viewfinder does not actually show exactly what the sensor is seeing or is the camera somehow reducing the viewing aperture of the lens?<br>

Cheers<br>

Ron</p>

<p>Many thanks for sharing your views, I'm more reassured that the thing doesn't just break spontaneously. I will set it to MF and leave well alone.</p>

<p>..just noticed my 85/1.4D also has a very similar ring - looks solid though despite 10+ years of regular usage... perhaps it's a better fit than the zooms and micro...Replacement of this cheap part looks like hassle - I don't see how it can be done without major disassembly...</p>

<p>That's good to hear.. I'm thinking of getting a macro slide rail for fine focus too, any recommendations?</p>

<p>Hi Shun, great photos!<br>

I appreciate your quick response. 7/8years sounds a little more comforting than 7 months...Did you use it normally like your other lenses, or were you aware of the collar issue and therefore extra careful with it?<br>

The 200 is my first ever micro and after a few test shots I already love the optics on this thing. Not just the sharpness but color rendition is amazing.</p>

<p>Hello Everyone<br>

Just received a brand new 200mm AF micro after a long and fierce battle with myself to justify the purchase... (fans of this lens will KNOW what that feels like, right?)</p>

<p>OK, so I was vaguely aware of the cracks on MF/AF collar from reading Bjorn Rorslett's evaluations but after stumbling on some of the threads on this site, it would seem that the breakage is more of a norm. BR wrote that the ring broke after 6 years even though it wasn't being used, other users reported breakages as early as a couple of months and in some cases, a couple of clicks! The list seems endless. So I would like to ask:</p>

<ol>

<li>Has anyone out there NOT had the thing break or crack after normal usage (say 2-6 years)?</li>

<li>Would leaving it on permanent MF setting, perhaps loosening the tiny holding screw a tiny amount (which some suggest is overtightened at the factory) likely to offset the risk?</li>

<li>Any other suggested remedies? Some mention the use of sticky tape to hold it together from the start.. but I wondered if there are more elegant solutions?</li>

</ol>

<p> ...I won't be losing sleep over this, but it would be nice to keep everything in one piece, I think everyone would agree that this lens is a thing of beauty....</p>

<p>Any comments welcome...<br>

Ron</p>

Ah well, off to the tech it goes then. And no, I don't think I've quite reached OCD stage yet but I may well have to be

treated for a cracked rib following the "floating element" comment:)

It's weird - almost like the rear element is mounted on some kind of tension spring which sits within the mounting ring and

holds the glass against the outer mount. It is only noticeable with slightly more pressure, it does not rattle or stay

depressed once you take the pressure off.

Hi Everyone,

 

During a routine clean, I noticed the rear element gives way slightly when pressed - rather like a button. The pressure applied was slightly

greater than normal (as I was cleaning a stubborn mark), but certainly not excessive. Apart from this movement (which stops dead at about

0.5mm), the glass does not seem loose and there are no loose artefacts/debris inside the barrel to suggest any damage or tampering.

 

I cannot for the life of me work out whether this is a fault, or some kind of design feature.

 

I always treat my gear with great care (verging on the obsessive), the lens was bought in mint condition from a dealer and has never

suffered in any way. All the screws are pristine and the mount is perfect. Had I not cleaned it, I probably would have been blissfully

unaware of this curious situation.

 

Has anyone ever come across such a thing on a lens? Please put me out of my misery.

 

Many thanks

 

Ron