Nikon D3 versus Canon EOS 1D - AF module

I do not own a Canon 1D Mark III or the Nikon D3, therefore my analysis below is just speculation, and should be taken with a pinch of salt.

Like everyone else, I have read the reports of AF problems with the 1D Mark III. The question is what could have caused these problems and how likely it is that the problems have been resolved in 1D Mark IV.

The AF sensor design changed between Mark II and Mark III. The design of the Mark II design is shown below, followed by the sensor design in Mark III (extract from Canon white paper).

Note that the cross-hair sensors are all clustered together in Mark II, whereas in Mark III, they are interspersed with line sensors. Now look at the Mark IV layout (from Canon white paper):

Although the Mark IV has more cross-type sensors, the layout in automatic mode is the same as that of Mark III. In manual mode, the layout allows more cross-type sensors to be used. The horizontal line sensors are usable with f2.8 and above, whereas the vertical line sensors are usable with f5.6 or above, except for the center AF point, which operates as cross-type upto f4, and as a line sensor upto f8.

Comparatively speaking, all of Nikon's cross and line sensors are fully operational at f5.6 and above.

My take is that the Mark IV may not provide as significant an improvement over Mark III as it could have. I think Canon should have clustered all the cross-type sensors in the middle, just as the Mark II did, and as Nikon D3 does. Another potential issue is the lack of vertical sensitivity below f2.8 in any except the central sensor.

Apart from the AF sensor and the AF algorithm, the other factor that affects AF performance is the mirror operation. The Mark IV specification of the mirror hasn't changed from Mark III. Blackout time is still 80ms, and shutter lag is still 55ms (with 40ms only at max aperture). It seems that the shutter lag is limited by the speed with which the aperture can be closed. Canon has maintained the top speed of 10 fps in the Mark IV.

The Nikon D3 has a shutter lag of 37ms and a blackout time of 74ms. Despite this, the D3's maximum firing rate is limited to 9fps, which means that the D3 has more time in between shots,  both for the mirror bounce to settle, as well as for AF calculations. Of course, we do not know how good Canon's mechanism is for reducing mirror bounce; the better this is the more time will be available for AF operation. It may well be that Canon's active mirror control mechanism, first introduced in the Canon EOS 1V, is more efficient than Nikon's.

For an interesting insight into Nikon's implementation, have a look at this video (credit: the video was posted at dpreview.com by user Tokyo24 on 28 Nov 2009):

Comparison of Viewfinder Magnifications in Nikon cameras

I think that the FM2N is probably one of the better cameras for manual focusing due to the high magnification of the viewfinder image of .86%. Compare this with .70% in D3.

The APS-C format DSLRs cannot be directly compared here because the specification of viewfinder magnification is in terms of a 50mm lens, but to get the same field of view as a 50mm lens on full frame, one has to use a 35mm lens on the APS-C DSLR. The effective viewfinder magnification of an APS-C DSLR is therefore lower than the specified one. Rough testing leads me to believe that the D300, for instance, which is specified as 0.94% magnification using 50mm, only provides an effective magnification of .75% when using a 35mm lens. This is not bad when compared to D3, but the Nikon FM2N is better for manual focussing.

Camera	Viewfinder magnification using 50mm at infinity	Viewfinder Coverage	Eyepoint
Nikon FM2N	.86%	93%	14mm?
Nikon FM3A	.83%	93%	14mm
Nikon F	.80%?	100%
Nikon F2	.80%?	100%
Nikon F3	.80%	100%
Nikon F3HP	.75%	100%	25mm
Nikon F3AF	.80%	92%
Nikon F4	.70%	100%	22mm
Nikon F5	.75%	100%	20.5mm
Nikon F6	.74%	100%	18mm
Nikon D3	.70%	100%	18mm
Nikon D700	.72%	95%	18mm
Nikon F90x	.78%	92%	19mm
Nikon F100	.76%	96%	21mm

Nikkor 85mm F1.4 versus 50mm F1.4 and 105mm Micro VR

I rented the AF Nikkor 85mm F1.4D and the AFS Micro Nikkor 105mm F2.8 VR over the weekend to try them out. Unfortunately, due to poor weather I was unable to shoot as many pictures as I had hoped. Nevertheless I was able to take some test pictures comparing the bokeh of the three lenses. The tests can be seen at:

Flickr Set 1
Flickr Set 2

Following are my general observations.

The 85mm has a very nice bokeh at F1.4, and it is sharp enough to be used at this aperture. However, there are color aberrations that are visible at maximum aperture. I found that it was difficult to get accurate focus on moving targets (a child) with this lens and the D300. Focusing wasn't slow as such, but somehow the camera did not track very well. This could be a user error as I am not used to taking action pictures. The lens is very well built, and is made of metal. I found that shooting subjects with a bright background created a loss of contrast due to flare. The lens I was using has a serial number 213792 and appeared to have been well used; so this could be just an issue with this sample.

Overall I was happy with the 85mm F1.4 but main concerns are ability to get correct focus and the color aberrations at maximum aperture.

The 105mm Micro VR is a huge lens. It is amazing how big it is compared to my 105mm F2.5 manual focus lens. It is fat and ugly, and looks too large on my D300. The lens appears to have at least part metal build; the focus is very fast at normal distances. The AFS motor just zips into focus; it is much faster than the 60mm F2.8 AFS lens, and the 50mm F1.4 AFS. Perhaps the size of the AFS motor makes a difference to the speed. This was my first experience with a VR lens; I was surprised to hear noises coming out of the lens when VR was enabled. For the test shots I disabled VR. I think VR is useful but I worry that it may make the lens more susceptible to break downs in the longer term. I also feel concerned that a VR lens by its nature is likely to suffer from centering problems, as the VR unit has to move up/down inside the lens.

From a bokeh point of view, I found that the 105mm Micro lens has a smooth bokeh, which can challenge the 85mm F1.4 at equivalent apertures. Of course, the 85mm has a larger aperture, which allows it generate the best bokeh (when used at F1.4) amongst the three lenses. The 50mm F1.4 generates the worst bokeh, as can be seen from the sample pictures.

The 85mm has the best build quality of the lot, and I hope that Nikon does not replace it with a more plastic bodied lens. As the construction is relatively simple and lacks a focusing motor, I presume that this lens is also the most robust and likely to survive the longest.

Ricoh GXR - a mistake?

I like my GR Digital III because it has a sharp fast wide angle lens. So much so that I am now thinking seriously about pairing it with a Nikon D300 equipped with a fast medium telephoto such as the 85mm F1.4 AF - this will be the perfect combination of portability and quality.

The recently announced Ricoh GXR camera doesn't excite me at all - in fact I think it is a very silly idea. Ricoh could have made a camera that used the Leica M mount, or even the micro-thirds mount. But to come up with a camera where the body itself has no functionality other than the display, the battery and the menu system is very silly, in my opinion.

The only cost saving it generates is for Ricoh. We as consumers must pay higher cost for the camera and lens combination; and new lenses will be more expensive than they need to be. And as many have pointed out, you do not want your lenses to become obsolete because the sensor attached to them is obsolete.

The quest for the ultimate film camera

Is the Nikon F6 the ultimate film camera?

Following features really interest me:

• Accurate metering - the colour matrix metering is supposed to be very good. The great thing about the F6 is that colour matrix metering works even with non CPU lenses, just like the D300/D3.
  
• Data imprint between frames - including date and exposure details - perfect!
• Interchangeable focusing screens - and a screen type that has a central micro-prism to aid manual focusing.
• Support for older non CPU lenses - and even non-AI lenses (after modification).

Other aspects that are equally interesting:

• Quiet and vibration free operation - I would love to compare the F6 with the Leica M6.
• Build quality - pro Nikons are built to last forever.
• Relatively small size as compared to F5, or the D series professional SLRs.

Pity that one can't rent the F6.

New ones are now exorbitantly priced - £1700 in the UK. That's the same price as that of D700.

I guess if you shoot film, then the F6 is the ultimate camera. It is perfect because it seems to have the best set of features amongst all film cameras.

Nikon D3s and Canon Eos 1D Mark IV

Nikon has lately been quite aggressive with its DSLR line, determined to hold on to its current market share I presume. Given that the imaging business is now the main revenue earner for Nikon, this is hardly surprising. I think that no one expected Nikon to completely revamp the imaging sensor in a point upgrade to the D3. A new FX sensor within 2 years of the old one, kudos to Nikon!

It is uncanny how Nikon and Canon appear to produce cameras with the same feature within a few weeks of each other. The Nikon D90 had HD video, and soon after the Canon 5DII came out with HD video. The same pattern has been repeated with the latest announcements - Nikon comes out with 102400 ISO, and Canon follows suit a week later.

Looking at the specifications, it seems that Canon has targeted sports photographers, sacrificing the FF sensor to keep to the 1.3x format. This along with the higher resolution should allow sports photographers greater reach and ability to crop.

The Nikon D3s, on the other hand, seems more targeted towards news photographers, although also thrown in is the 1.2x crop mode as a convenience to sports photographers. Thanks to the upgraded imaging sensor, the D3s is able to compete with the 1D Mark IV, despite being a two year old model.

Only time will tell which of these design choices is a winner.

Canon has an obvious advantage when it comes to the video implementation, due to its long experience with professional and amateur video cameras. But quite apart from this, a bias may be evident in how the video has been executed. The Canon appears to be targeting Videographers, whereas the Nikon is targeting primarily still photographers who want to take advantage of the occasional video.

These are just speculations on my part; it is unlikely that we will ever get to know the real reason for Canon sticking with the 1.3x format sensor, or for Nikon avoiding the 1080p HD video format. If I were to hazard a guess, I would say that Canon believes 1.3x format is better for sports photographers, and had not anticipated the upgraded D3s. A 1D Mark IV with support for 102400 ISO and HD video, compared with the original D3, would have been a clear winner.

The introduction of D3s just before the announcement of the 1D Mark IV has despoiled Canon of a clear victory here. But Nikon's choice of 720p format video is puzzling. My guess is that the Expeed chip isn't fast enough, and that we will not see 1080p HD video until the next generation Expeed chip comes along.

The best thing with these two cameras is that each has its strengths, and there is no clear winner. Therefore photographers using either brand can get on with the job of taking more photographs, rather than agonizing over the superior features of the competitive brand.

Nikon would hit a home run if they introduced an upgrade to the D700 with the same sensor as in D3s. I for one would buy such a camera immediately. The D3s is too serious a camera for an amateur like me, therefore I could never justify buying one.

Ricoh GR Digital III - Part 4

Things about GRD3 that I wish were different.

• I wish the lens cap was a bit less fragile. As it stands, I feel scared that something will push it in and scratch the lens.
• The LCD can be switched off using the custom settings; but when you do so, it stays off and there is no way to check the camera settings, which makes it less than useful. I wish there was an option to just display the camera settings on the LCD rather than being completely off. As it is, I think it is better to leave the LCD on even when using the external viewfinder.
• Wish the external viewfinder were povided with a central AF square - as this would really make it useful in spot AF mode. As it is one has to guess where the focus point will be. 
• Now this is an odd one; I actually wish that the lens did not retract into the body and was completely fixed instead. This would make the lens more sturdy and the camera would be more responsive. But this would of course completely destroy the compactness of GRD3.