In an earlier post of photos taken with a Fuji X100, the megapixel question came up, and as this is something I've been spending a lot of time contemplating recently, I thought maybe a discussion thread was worth opening up on the subject, principally concerning the D800 and alternative approaches, or indeed needs.
As some might know, owing to the improbably large files I've been generating over the past few years with multi-row stitched and focus-stacked panoramas, at the end of last year I bought a latest upspec PC, (12 cores @ 4.3GHz through 64GB RAM & SSD) which just, and I emphasize just, made working these panos taken with a D3s (i.e. 12MP files) practical. The biggest pano involved 240ºx160º field of view and comprised some 625 individual photographs, some focus stacked with up to 11 steps. It was the image that prodded me into upgrading the computer, because processing on my previous 8-core 2.66 GHz 12GB RAM machine had been impossibly slow.
But the D3s has some drawbacks: it is heavy to carry, and on the Nodal Ninja Ultimate panoramic head it is imperative to use the mirror up function with at least a slow 2-count pause before releasing the shutter. There is no room in one of these sequences for even one vibration-affected frame. In a photo with moving objects and less than still air, the slowness of operation thus caused can become a real problem (this shot took 29 minutes to take, moving as quickly as I could).
Of course with a slow taking sequence things like a sunrise (or sunset) become something that must be planned and prejudged exactly to even work, as the earth's rotation cannot be put on pause. I think there were close to 300 shots in this sunrise, and that it worked at all still leaves me slack-jawed (took about 12 minutes to expose moving top left to bottom right, along with a three hour return hike the evening before to work everything out so the pre-dawn setup wouldn't be guesswork):
Now enter Nikon's release of the D800E. On the face of it the extra resolution & modified anti-alias filtering was oh-so appealing (though I'm not sure why, as the human eye doesn't have a 100% function), along with the draw card of its 14+ stop dynamic range. I was on the cusp of ordering one, but delayed to allow production to bed in, and this delay let the misgivings I had filed into the "do not think about" basket bubble to the surface. My supplier's attempt to interest me in a wide-angle attachment for my Fuji X100 led me on to investigate the new Fuji Pro X1, sweetened by Fuji's promise of a Leica M mount adapter, along with a plethora of 3rd party adapters for umpteen other lens mounts.
So I took more interest in my X100 and tried to envision how a mirrorless rangefinder camera with a hybrid viewfinder might fit into the scheme of my "serious" photographic work.
Yesterday I set up the X100 on the Nodal Ninja pano head in the backyard and did a really rough 360º spherical set of exposures (74 all-up). Focus stacking is not an option with this camera given that any "manual" focusing involves turning a focusing ring which in turn has the AF motor moving the lens, which is jerky and after-thought style stupid. However a manual focus legacy lens will not have this drawback on a Pro X1.
Getting to the point of all this now was that taking the pano was simply lightning fast compared with the mirror-up~...wait~....release of the D3s. Triggered with a good old-fashioned screw-in type cable release, the only problem was not vibration (zero) but rather knowing that the camera had taken the exposure at all, the shutter being so quiet. The X1 will be louder, and this is not a bad thing in this instance. Or alternatively the sonic fake shutter sound could be set in the menu, of course. All 74 shots were completed in 5 minutes flat, including a couple of pregnant pauses where I wondered whether the shutter had gone off at all, and also fiddling with the pano head to adjust for the vertical rows. The desire for the D800E was teetering...
So to image assembly - the X100 takes 12.2MP size files. The computer had no problem with this, but the end file size was still a tad over 2GB. So the 16MP Pro X1 using a similar focal length will have one of these spherical panos using a 23mm lens in at around 2.75GB, and for a D800E we're looking at around 6.6GB by simple multiplication - but probably not all that much larger if a 23mm lens was used as the sensor covers more real estate with each shot. However this is getting ridiculous for something to be printed out at a maximum of 24" high @ 288ppi, or worse, made into a quicktime pano tour web-size movie of around 1MB. Even a 44" high print would probably be over-serviced. Have you ever tried to sell a 44"x 8' print? Very small market for this. Tiny, even. As small as the print is large.
If I were trying to enlarge a single frame to 34"x24" perhaps the D800E would make sense, but fact is that I rarely do this, and even when I have the D3s files have posed no real problems getting there. Sure, they might not hold up as well under inspection-glass scrutiny, but at a viewing distance of a couple of feet or more, no problems whatsoever. Even though using the same focal length might result in fewer photos needed overall with the D800E, if focus stacking each shot was part of the equation there would be the need to process these full-size D800E files, so a stack of 12 would involve churning around roughly 2.4GB of info in the form of Tiff files. A pano involving stacks from 1" to infinity would be a nightmare, but this is something I'm working on at the moment. Even though there'll be more individual stacks involved, the ~100MB Tiffs from a 16MP camera will be a lot more machine friendly than doing this with 36MP files. Same goes for HDR stacks.
The backyard shot below started out at 27771 pixels wide, hammered down to 1389px if expanded by clicking on the forum thumbnail further hammered down to that shown here, so forget about judging image detail & sharpness, just take my word that both are here in spades on the original (the DR is, however, very evident, and yes, I'll paint the shed one day, after I repaint the roof and everything else that a 132 year old house needs in ongoing maintenance
):
I had made a lo-res *.mov "tour" file of this but the website refused to upload it (format incompatible?) so the smudge bottom & top won't make sense, but the tripod is what's stretched along the bottom, and I didn't bother with either "nodal" shots to cover the tripod over or the zenith circle either.
Edit: I'll also add this 100% section (click on it to see at it's 1000px width) to back what I said about resolution and to give perhaps a better idea of just how big this image is at its native resolution, the dam & post gives the position of this away with regard to the rest of the picture (remember, this is from a 12.2MP camera):
Now the Pro X1 has allegedly got the best sensor ever seen in an APS-C format, and given the way that the X100 handled this rough & ready 360º shot covering deep shadow to straight into the sun (no planning at all, only the most cursory exposure reading & setting), I'd have no fear that the Pro X1 will be more than capable of even better. So I'll probably order one next week.
Also the 23mm lens on the X100 is too wide for panos with minimal distortion (crop factors are meaningless here outside of the number of shots required, 23mm is 23mm which causes almost unacceptable anamorphic distortion in panos - or horizontal compression, to put it another way) - 35mm is my preferred focal length as a balance between anamorphic distortion and sheer numbers of photos required to cover the real estate, and thus also the end file size. So in fact we're talking even bigger unsampled end file sizes anyway... the first photograph at the top was taken with a 50mm lens to completely wipe out anamorphic distortion, which helps account for the huge number of shots required (aside from the stacking involved). Of course the smaller APS-C sensor on the Pro X1 will require even more shots to cover the same real estate were I to use a 50mm lens, and were I to contemplate a 4/3rds camera, even moreso again.
So assuming a 35mm lens will be the best compromise, I have a 35/1.4 AI-s which I bought brand new at end 2010 and will fit a Pro X1 via adapter, and I possibly will nevertheless also contemplate the Fuji's "standard" 35/1.4 as well for those AF-type shots away from the pano head. Whatever, the D800E would appear to be off my shopping list now as being less practical for this sort of thing.
Swings and roundabouts, nothing's ever simple, is it?
This post has been promoted to an article
Edited by Fred Nirque, 09 July 2012 - 02:13 .
