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Going Over Material, Updates Soon

Get Nikon D810 at B&H Photo.

I finished my catch-up work today (always a chore after being gone ~11 days), and now I’m going through my trip material with a lot of stuff to come soon on the Nikon D810 and Pentax 645Z.

Nikon Capture NX-D: DOA

Get Nikon D810 at B&H Photo.

I did a previous piece on Nikon Capture NX-D versus ACR. But today, to verify some shooting settings, I wanted to open some D810 NEF files in NX-D. For whatever reason, every NEF file is refused by NX-D now (and on both my desktop and laptop, this is not machine specific). There are no updates and the current version of NX-D is installed. OS X 10.9.4.

  Nikon Capture NX-D: every Nikon D810 file fails
Nikon Capture NX-D: no Nikon D810 file can be opened

Are the Capture NX-D and Sigma Photo Pro software development teams secretly trading notes on worst practices? Given the existentially threatening 26% drop in Nikon revenues, one wonders if the issues are company-wide at every level and type of function. It’s a scary thought. Readers know that I appreciate the Nikon D810 image quality (a new high bar in the industry). But how such basic software flaws can go undetected for weeks is a stunning indictment of quality control practices. And then there is the white spot recall at the outset. Taken as a whole, the picture looks indicative of Something Generally Amiss in Nikon land.

It’s bizarre that NX-D cannot open NEF files, since that is its raison d^etre. I used “Open With” and chose Capture NX-D (this is a workaround and should never be necessary): from the start, Nikon Capture NX-D would not associate NEF files with itself (the system does not recognize that NX-D is for opening NEF files, the file type association is not there).

  Nikon Capture NX-D: does not associate with NEF files!
Nikon Capture NX-D: does not associate with NEF files!

Nikon D810 Service Advisory for White Spots During Long Exposures, and 1.2X Crop

Get Nikon D810 at B&H Photo.

  Nikon D810
Nikon D810

After the Nikon D600 dust/oil fiasco, this is another black eye for Nikon. But this time the recall/fix is immediate, and that is a far smarter move than the defensive and prolonged pushback with the D600 oil/dust issue.

Nikon has issued a service advisory for the D810:

We have received a few reports from some users of the Nikon D810 digital SLR camera indicating that noise (bright spots) are sometimes noticeable in long exposures, and in some images captured at an Image area setting of 1.2× (30×20).

After looking into the matter, we have determined that some noise (bright spots) may on occasion be noticeable when shooting long exposures, and in images captured at an Image area setting of 1.2× (30×20).

Nikon service centers will service these cameras that have already been purchased as needed free of charge to the customer. We sincerely apologize for any inconvenience this issue may have caused.

Identifying affected products

To check whether or not your camera is one of those affected by this issue, please click the Affected Product Serial Numbers link below and enter your D810’s serial number as instructed. Your camera’s serial number will be checked against those of affected products. If your camera is one of those affected, you will be forwarded to additional instructions. If your camera is not one of those affected, you may continue using your camera without concern for this issue.

DIGLLOYD: In my testing of the D810 I observed no white spots, so I thought that the camera I am using is fine. But I have always used long exposure noise reduction with the D810 (and all cameras I test). LENR differs in nature from regular noise reduction; LENR is a dark-frame subtraction. Nikon does not speak to LENR or not.

The loaner camera from B&H that I have been using is included in the recall (I entered its serial number). Now I have to decide wether to buy/repair or just get a replacement. I just hope that my trip photos are unaffected. But it’s an issue: I cannot let go the D810 at this critical time for some unspecified turnaround period. And while UPS ground shipping to and from the Los Angeles service center is fast for me, for a working professional that is more remote it is offensively slow (no option offered).

It’s also troublesome that one has to log in to check the serial number: how to know if a camera at a store has the issue or not? The Nikon site is also a shambles; it continually gives me “unspecified error” when I try to access my account settings to correct my email address as well as other errors in various places. I had to reconfigure my mail server to use an old email just to get the *#*$#*$* password reset email required by Nikon due to “system changes”.

Miguel B writes that “Apparently the cameras known not to have the issue, or recalibrated (whatever the solution may be) have a black dot inside the tripod screw.”.

Update: I called Nikon and was told that turnaround time is 7-10 days and that the fix is a firmware update. I was promised a Level III tech support return call (I have various questions about the circumstances under which the issue occurs), but this did not happen.

  Nikon D810 recall for white spot issues
Nikon D810 recall for white spot issues

Understanding the Pentax 645Z Histogram (useful for any brand camera)

This is a shot discipline and technical execution article that should be assimilated by anyone shooting raw on any brand camera.

This discussion of post-shot and Play histograms on the Pentax 645Z also incorporates the RawDigger histogram and a discussion of color space and gamut and recommended practices for raw shooters.

Interpreting the 645Z Histogram

While this is a Pentax 645Z image, the discussion is useful for any digital camera. And while it is not a field image (landscape or similar), the genesis for this page was observing histogram variances during field shooting; this histogram variance is discussed and shown for this image, but occurs with all images.

The image shown below is perfectly exposed yet the histogram suggests that the red channel is slightly blown; in fact the green channel is most at risk by about half a stop. The discussion explains the reasons and the fundamental algorithmic flaws in virtually all camera implementations of the histogram (for the raw shooter).

  Rain-streaked Aspen Trunk Pentax 645Z + 90mm f/2.8 @ ƒ/8
Pentax 645Z histogram

Lawrence B writes:

Thank you for your extremely useful article ‘Interpreting the 645Z Histogram’. I believe this is the first time I have ever seen in print reference to this most disturbing discrepancy between the ‘before and after’ histograms as displayed on most digital cameras.

Though I do not own the Pentax 645Z (I use a Nikon D800E), the differences observed have been most confusing, and though one can always check later (via RawDigger) histograms based on the RAW data, this helps one little when out ‘in the field’.

Unfortunately, you didn’t offer an explanation as to why the post-shot histogram differs from the one shown during live view (the ‘play’ version). Both are regrettably based on the camera’s JPEG settings. Shouldn’t their ‘inaccuracy’ compared to the RAW data based histogram be identical? Why is the live view histogram somewhat less inaccurate than the post-shot histogram?

I don’t understand why the industry has been so reluctant in offering a histogram based on RAW data. Photographers have been requesting such an option for as long as I’ve been shooting digital (probably longer). In any case, I am most appreciative that you tackled this disturbing phenomenon of the differing histograms. The tips you offered are indubitably the best one can do under the given circumstances. Many thanks!

DIGLLOYD: Yes, other cameras exhibit similar behavior.

As with science, an observation must come first, but an observation does not produce an explanation. Saying “I don’t know” is often the reality. It’s on my “why” to-do list.

The 645Z was configured to shoot DNG only (not DNG + JPEG), so it cannot be the result of the embedded (within the DNG) JPEG versus a full size companion JPEG.

That leaves a camera processing algorithm, and only Pentax can say for certainty, but a reader out there might have a credible explanation. My speculation is that the Play variant is based on the JPEG embedded in the DNG (since it is clearly in the color space with which the camera is configured, AdobeRGB), and that the quickie post-shot variant is based somehow on the image processing pipeline as it “flows through” and/or on every other sensor line, or some other efficiency optimization.

See also true raw histogram.

Back from Trip

Back home, unpacking, downloading, etc.

  Shooting the Pentax 645Z near the Pine Creek Tungsten Mine iPhone
Shooting the Pentax 645Z near the Pine Creek Tungsten Mine
iPhone

Wrapping up Field Shooting

Up in the mountains field shooting.

Just about done and heading home tomorrow. Long days were productive, now it’s computer time with all the material I’ve shot.

Field Shooting the Pentax 645Z

Up in the mountains field shooting, writeups follow when I’m back in a week or so.

I’ve been shooting the Pentax 645Z alongside the Nikon D810 in many situations and I’m gaining a solid perspective of the two cameras. Nikon D810 with Zeiss Otus or Pentax 645Z with the excellent 90/2.8? Lots of factors to consider.

  Rain-streaked Aspen Trunk Pentax 645Z + 90mm f/2.8 @ ƒ/8
Rain-streaked Aspen Trunk
Pentax 645Z + 90mm f/2.8 @ ƒ/8

Bobby N

Beautiful image. My D800E with Zeiss glass just can't evoke texture like that. Darn.

DIGLLOYD: The 90mm f/2.8 on the 645Z is equivalent to a ~72mm lens on a DSLR. So right off that bat the perspective and blur qualities differ by distance/perspective. Second, depth of field is a challenge on the 645Z and the image requires more stopping down (to ƒ/11 or ƒ/16) to make the trunk fully sharp everywhere (e.g., bottom area), and this then diminishes the gorgeous blur differentiation between foreground and background. I shot the entire series from ƒ/2.8 to ƒ/11 and will be showing it all—very interesting stuff IMO.

The 50/2 Makro-Planar is an outstanding lens with some edge and corner rearward field curvature, but only the Zeiss Otus 55mm f/1.4 APO-Distagon outperforms it in micro contrast, and that difference is very small once stopped down to ƒ/4. So to say the 50/2 cannot produce an image like this is not a premise I am prepared to just agree with offhand, particularly on the Nikon D810. Yes, the 645Z and 90/2.8 are “special”—absolutely and in my view the Pentax 90/2.8 is the lens to have for the 645Z. But one has to A/B shoot to really get a sense of things, and not just one scene.

Next, the appropriate comparison for a $4500 medium format lens is to the Zeiss Otus line (about $3990), so naturally I shot this scene with Otus also.

The question/premise above is of keen interest to me and others, so in my recent field work I’ve made a point of many A/B scenes between the Nikon D810 + Otus and the Pentax 645Z and 90/2.8. These will take time to assess and publish, but by mid September I expect to have have published a goodly number of compelling scenes to investigate this question.

Reader Question: Image Brightness at Full Aperture vs Stopped Down

Up in the mountains field shooting, writeups follow when I’m back in a week or so.

Sunil A writes:

I am a diglloyd subscriber, I immensely appreciate and admire your work. I am not a pro, but I am photography enthusiast and like the technical aspect of DSLRs, I find your blog and DAP very educational.

Since you have been using D810 for couple weeks (I am a regular blog reader), I thought to inquire about an issue I see. I have D810, Nikon 70-200mm VRII, Sigma 35mm 1.4 A and Nikon 85mm 1.8g. I was testing D810 with 70-200mm, I consistently find images darker shot at maximum aperture. In Aperture priority mode, going from F 2.8 to F 4, the shutter speed is doubled but the images are brighter. Compared to F4, F2.8 image RGB is more towards left.

Maximum aperture on a lens may not be real maximum (T Stop). So is the camera looking at marketed aperture vs T stop. And later at F4.. is the T stop and F stop same.

So do you always do exposure compensation to get the same exposure between apertures. I find your images to be exposed the same across apertures.

I found the same issue on Sigma 35mm 1.4 as well, although not to the same degree as Nikon 70-200mm. I appreciate your advice, as I am not sure if it is just my camera. I also posted a thread with images on dpreview as well.

DIGLLOYD: First, I’m assuming that “shutter speed is doubled at ƒ/4” means twice as long, so that the exposure value (EV) is equivalent, e.g., ƒ/2.8 @ 1/500 vs 1/250 @ ƒ/4.

At full aperture, several effects are at play. I regularly compensate for this by giving 1/3 stop to 1/2 stop or so more exposure at full aperture for some lenses (particularly wide angles), though I usually reverse that boost when doing a series. I do so to give better exposure to the peripheral areas. The amount needed ranges from almost no compensation to nearly 2/3 of a stop with certain wide angle designs. How much depends on the lens design and the particular sensor. Across an aperture series, it is common to see fluctuations of 1/10 or 1/20 stop from other factors (e.g. diaphragm and shutter speed accuracy); I normally correct this kind of normal variation for presentation.

Why darker?

Vignetting (field illumination) is a multi-factorial behavior; primary losses quickly improve even one stop down. But this does not account for center brightness. See also Ray Angle, Vignetting, Color Shading on a Digital Sensor.

Sometimes there is plain old “cheating”; a nominal f/2.8 might really be f/2.9 or f/3 but vendors prefer to state a nominal value. Sometimes this derives from rounding the focal length figure, e.g., 50mm might be 48mm or 52mm, or 200mm might be 180mm (!). Up to 10% is considered “acceptable” (by whom?). But it might also be rounding off the true diameter of the lens diaphragm. Since f-stop = focal / entrance pupil diameter (a ratio), judicious rounding can go a long way when it sounds better for sales. Basically, conventional numbers sound better; no vendor wants to advertise an ƒ/2.9 lens.

Then there is transmission (T-stop) which can reduce whatever brightness is actually there (see What are F-stop and T-stop? in Making Sharp Images). T-stop is typically only 1/10 stop less than f-stop Zeiss ZF.2 lenses, but few other vendors say.

Then there is the loss due to digital sensor technology and peripheral ray angle, which can be up to half a stop for some f/1.2 lens designs and remains very significant at ƒ/1.4.

Many vendors silently adjust for their own brand lenses and/or chipped lenses from others. For example, Canon silently gains-up the f/1.2 lenses to compensate! This can be seen by inserting paper between the lens contacts and camera body; the camera not recognizing the lens won’t make the silent boost (compare with/without). Many point and shoots and other cameras (e.g., Fujifilm X) just build in correction for their own lenses (and also vignetting correction on top of that), whereas in reality the true brightness might be significantly less than advertised. Hence it's rather silly to see “lens tests” for vignetting with some cameras where the vignetting has been taken out by the camera already. Such tests are system evaluations, not optical.

Nikon D810: HDR in One Exposure?

Up in the mountains field shooting, writeups follow when I’m back in a week or so.

It’s fascinating just how good the Nikon D810 is for scenes that would require the hassle of HDR bracketing and post processing (Canon users fall about 2 stops short of the D810 and with a ton more noise in shadows). The Nikon D810 at ISO 64 has a stunning dynamic range.

I plan on showing how to make full use of the D810, starting with exposure: Nikon has designed the D810 histogram very badly, so as to fool you every time into wasting 1 to 1.5 stops of headroom even as the camera shows “blown out”). And how to make this sort of adjustment in Adobe Camera Raw (same approach in Lightroom).

This particular image was the brightest one of a bracketed series: I was sure it was blown out, since the histogram said so. But it is not so! There is even more than 1/3 stop of additional headroom remaining, according to RawDigger. No highlights are lost and no shadows are pinned, as the raw data shows. Yet the shadows in the brightened “faux HDR” image control noise very well—impressive considering the almost pure black in the darkest areas.

Toggle to compare the as-shot image to the one given a massive adjustment.

Note: prepared after a long long day hiking in my car approaching 10pm; hard to evaluate best contrast, brightness, etc, so this is a quickie that no doubt can be improved upon further.

  Sun Over Pine Creek Illuminates Field of Sunflowers Nikon D810 + Zeiss Otus 55mm f/1.4 APO-Distagon

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