At last I managed to get out and do a bit of shooting with the D800 and a couple of lenses during gaps in the rain and between other commitments.
I have wanted to get some Autumn images in the New Forest so combined this with some lens evaluations on the camera. Conditions were hardly ideal but the chance to get out was just great! Forest is an interesting test of a camera & lens combination due to the darkness, combinations of deep shadow and bright highlights, colours, complex detail and patterns and the very three-dimensional nature of the subject. As usual with this camera (and essential for evaluating lenses) I used a tripod, remote release and live view to focus. Focus was manual as the tested lenses are manual only.
First I used the Carl Zeiss 35 f1.4 Distagon. This is one of the newer lenses in the Zeiss ZF line and I love it with no reservations. I have already used it on the D800 where @ f8 it rendered the highest level of detail I have ever seen from an SLR to date, but I wanted to try a variety of wider apertures to give it a good workout and because I love that style of photography.
Zeiss 35 f1.4 @ f2.8 focused on tree trunk approx 1/3rd up from ground. The sharpness within the field of focus is excellent and is very close to the maximum attainable with the lens. I also love the subtle, smooth fall off into blur. Colours look natural and rich and the tones have been handled very well by the camera and lens. There was quite high contrast in this scene and all I had to do was pull back some sky highlights. Chromatic aberrations are very low with this lens and only some purple/blue fringing was evident in a few places of extreme contrast, but in spots rather than along whole edges.
Zeiss 35 f1.4 @ f2. Another stop wider and this time focus was on the horizontal bough at approx centre. Sharpness and contrast is very good but slightly below what the lens is capable of. Subtle traces of the wide open spherical aberrations are still there but clean up easily with a little bit of extra sharpening. We see a more rapid fall into more obvious blur here due to the wider aperture and closer subject. To me, the f2 and wider shots are what really defines the character of the Zeiss for SLR lenses, with the in-focus subject standing out clearly from a defocused background and a falloff into blur rather than a "flat" smooth bokeh. I won't have a heavy, expensive f1.4 lens to shoot at f8 all the time! Again there was a big contrast range in this image and it hardly needed any work as the D800 files are that good.
Zeiss 35 f1.4 maxed out at f1.4. Focus was on the large trunk 1/3 of the way in from left. Wide open this lens does have uncorrected spherical aberrations, most probably as part of the design, to give it two characters; one wide open, one stopped down. However these aberrations are not extreme and as long as focus is nailed the image can be made sharp with good contrast from wide open. There is certainly masses of resolution which is slightly softened by the halation. The aberrations sometimes make accurate focus a bit ambiguous in darker conditions or where the subject lacks higher contrast detail. However, live view focus is generally accurate and fairly easy to achieve even at f1.4. Falloff into blur is even more obvious on the D800 than my lower resolution bodies as the fine pixels show softening earlier in the defocused areas. This lens does not vignette to anything like the level of many other Zeiss primes...it is there but more subtle.
Here is a 100% crop of the tree trunk in the focused area. Note how limited the DOF is even though the subject is not especially close.
I was also interested to see how the Zeiss 85 f1.4 would cope with the resolution challenge posed by the D800. This is a lens of classic design (primarily for portraiture) and quite a simple optical formula with an extreme example of dual character due to very significant spherical aberrations wide open. At least using live view I was able to by-pass the real user headache with this lens...the rather extreme focus shift stopped down to f2.8 and beyond.
Zeiss 85f1.4 @ f2. Focus was on the dark tree stump just left of centre. One stop from wide open the spherical aberrations have cleaned up less than the 35 Distagon but the rendering is very usable for general photography. Focus ambiguity is more extreme than the 35 f1.4 when wide open but it is still quite easy to get good focus in live view. As long as focus is accurate resolution is actually very good indeed and the falloff into blur gives the scene real perspective and depth. The lovely tones of the fallen logs in the foreground and the colour and perspective of the carpet of fallen leaves look outstanding to me. I do prefer the bokeh of this lens at f2 generally, as sometimes its a bit fussier wide open. A vignette is subtle but there...again I love it.
Zeiss 85 f1.4 again at f2. Focus was on the bark of the tree stump....this must have been a dramatic collapse as two very large trunks had broken off and landed in opposite directions! I took shots at several apertures but preferred the f2 version over the wider and narrower aperture shots due to its decent sharpness, dramatic subject separation and lovely fall into blur. f1.4 on this lens is definitely more the classic portrait look and I prefer f2 for landscapes. f1.4 is usable for landscape and may be right for some subjects but I would use it very selectively where I wanted a slightly dreamy look.
For reference here is a 100% crop of the image taken at f1.4 which shows the rendering of the lens wide open. There is actually a lot of resolution but it is clouded slightly by the halation of spherical aberration. Remember, this is a 36MP sensor so the 100% image is a ruthless magnification.
Finally here are examples to show the effects of diffraction on the D800 files. I think the Zeiss lenses are more resistant to it than many lenses might be due to their excellent optical quality. Diffraction obviously has to be considered in perspective...the resolution of a file shot at f16 is still amazing. I would be happy to stop down if I needed to but its important to understand that the full resolution potential of the sensor does suffer and a subject can be rendered more dramatically if shot at f4-5.6.
Zeiss 85 f1.4 @ f5.6
Zeiss 85 f1.4 @ f16
Zeiss 35 f1.4 @ f4. This subject was toward the right of the frame and not in the centre so it is possible that the f4 file does not reach the max quality that can be achieved more centrally. However, the difference between f4 and f16 is still obvious.
Zeiss 35 f1.4 @ f16
I consider both the 35 f1.4 and 85 f1.4 to be great partners for the D800. The 35 is very usable from wide open and sharpens slightly through f2.8 while retaining that dramatic subject and background separation. The centre probably improves technically through f4 and f5.6, though it isn't really noticeable, but global sharpness over the frame clearly improves, partly due to increased depth of field. Other images I took today showed that at f11 it retains lovely central sharpness but the borders and even the extreme corners sharpen right up for landscapes as long as the corners are in the focus field.
The 85 renders lovely images on the D800, full of perspective and punchy, colourful tones. For my taste I prefer it stopped down to f2 for landscape as the f1.4 rendering is just a bit too 'classic portrait" for most scenes. The lens sharpens progressively to a peak at perhaps f5.6 or f8 globally but f2 renders lovely separation and falloff with a very decently sharp subject.
Despite their differences in rendering at the wide end of the aperture range, both lenses have the signature Zeiss family look and its good to have a range of lenses where the colour, contrast and drawing style is so similar.