I had been very interested in this lens for a while as it seemed to offer an interesting combination of portrait and close-up capability for larger macro type subjects such as dragonflies and flowers. As a very happy user of the Zeiss 85mm F.4 Planar I had an idea of what to expect.
All reviews I have ever seen give it a huge "thumbs -up" and the excellent Lloyd Chambers gives it stunning reviews in his comprehensive Diglloyd website, dedicated to photographic technique and equipment in real-world use. In fact he clearly sees it as one of the best SLR lenses available at any price for its ability to out-resolve current DSLR sensors from wide open, its bokeh, subject isolation and mechanical quality.
An excellent local photographic dealers (Robert White, Poole) ran a Zeiss day last week and it turned out to be a hugely useful experience, with access to all the Zeiss SLR lenses, great staff on hand to assist, well-known and very personable landscape photographer Jeremy Walker and a mini studio with a pretty model for trying one's hand with the different kit.
What did I think?....I was perhaps more overwhelmed by the performance of this lens overall than any other I have tried and this impression was both immediate and is increasing with use.
It has that amazing Zeiss rendition where the micro-contrast seems to pop and separate the subject from the rest of the image. It has amazing sharpness and contrast across the field on full-frame, from wide open at its very fast max aperture of F2. The depth of field control and bokeh is simply amazing....apparently this lens has an Arri-Zeiss optical design based on that used in motion picture industry lenses, which are very expensive and this design is used to knock backgrounds out of focus. It has the ability to cut an incredibly thin swathe of razor sharp focus right through an image, while rendering the rest as a pleasing blur. Performance both close-up and at infinity is to the same standard.
The focus action is absolutely sublime, with a firm, silky smooth and long action that easily enables precise focus. The build is awesome....a chunk of heavy glass and metal with the density of a black hole but surprisingly compact and manageable.
When Stu at Robert White kindly printed off one of the mono images for me (with virtually no PP) on an Epson 3880 from Lightroom onto Ilford Gold Fibre Silk paper...that final result in print was the ultimate tribute to the lens and I knew I had to have one in my bag.
To be honest you could talk about it all day but the images really speak for themselves. My brother is a very competent and keen photographer and he saw something special in the image quality even when previewing one of these portrait shots as a small Jpeg on Flickr. The quality is a composite of all the qualities mentioned above but I think that more than anything, its the style of depth of field control that really makes this lens unique.
Of all the lenses I have used I would say that this is one that any keen close-up or portrait photographer should get as a priority and even if you don't see yourself as either of those, its the sort of lens you will always find a reason to use and learn to love. I have a baby on the way in September and can't wait to use it for both detail and portrait shots....oh and before then the dragonflies should be out if this winter ever ends!
Simply superb!
Tuesday 23 March 2010
Tuesday 16 March 2010
Depth of Field versus Diffraction
After critically examining some landscape images I took a couple of years back I was disappointed with their critical sharpness, specifically on the Tokina 12-24 lens , which I use mainly for landscapes on my D80 & D300.
Initially I thought the lens was less than great, but I did some research into the effects of diffraction and after a bit of experimentation, realised that it was diffraction having its wicked way with the resolution I was getting...not a faulty lens.
What is diffraction? Well my understanding is that its a physical limitation that cannot be stopped and means you have to use your lens in ways that avoid its worst effects. Basically, its the effect of light rays passing through the pupil created by the aperture diaphragm and as the ray contacts the edges of the pupil, it scatters slightly. When this scatter exceeds the dimensions of a pixel its getting destructive, as the light ray is spilling onto adjacent pixels instead of falling on only one. Therefore cameras with very high pixel densities are worse affected. When the aperture diaphragm is wide open the proportion of light rays that contact the edge of the pupil is small compared to those passing undisturbed through the large pupil. When the aperture is stopped down, the proportion of rays contacting the pupil becomes much higher compared to those passing undisturbed...hence a higher proportion are scattered and diffraction gets worse.
When doing landscape shots on a tripod and including some foreground interest, I was routinely stopping down to F14 and even F16 and F20 on my DX (APS) sensor cameras. This was mostly out of "making sure everything would be in focus" by extending the depth of field...playing safe.
If you look at any lens tests on APS sensor cameras its quite obvious from the MTF plots that diffraction starts to creep in and rob images of sharpness as low as F8. Beyond F11 it really starts to get destructive and F16-22 is simply a no-go zone. If you have a 12MP SLR, let alone a 16, 18 or 24MP SLR your lens will nowhere near out-resolve the sensor and will be the limiting factor in sharpness and resolution.
I did some tests with my own 12-24 lens and found that sharpness held up well to F11, then declined. I was keen to see if this limited my depth of field enough to prevent me getting sharp images with close foreground interest, while still retaining sharpness at infinity.
I was surprised to learn that with careful focusing I could easily get objects in focus from around a metre away to infinity at F11. That was more than enough in all but the most close-up of situations. To make sure I nail the focus I often shoot in manual focus and set the distance scale so I'm not wasting DOF by focusing beyond infinity. I often shift the focus point and use the focus indicator on both the close and distant subject to confirm focus, before shooting.
In this image the Lion was under a metre away and even at F9 both it and the house are in focus at 12mm focal length. The image is sharp and has good contrast.
On full frame cameras diffraction effects tend to kick in perhaps a stop or two smaller than on APS cameras and many better lenses hold out to F16, but of course there is less depth of field anyway than on an APS camera.
As a result of this understanding I never stop down unnecessarily now, try to optimise my DOF and get better image quality as a result. Give it a try.
Initially I thought the lens was less than great, but I did some research into the effects of diffraction and after a bit of experimentation, realised that it was diffraction having its wicked way with the resolution I was getting...not a faulty lens.
What is diffraction? Well my understanding is that its a physical limitation that cannot be stopped and means you have to use your lens in ways that avoid its worst effects. Basically, its the effect of light rays passing through the pupil created by the aperture diaphragm and as the ray contacts the edges of the pupil, it scatters slightly. When this scatter exceeds the dimensions of a pixel its getting destructive, as the light ray is spilling onto adjacent pixels instead of falling on only one. Therefore cameras with very high pixel densities are worse affected. When the aperture diaphragm is wide open the proportion of light rays that contact the edge of the pupil is small compared to those passing undisturbed through the large pupil. When the aperture is stopped down, the proportion of rays contacting the pupil becomes much higher compared to those passing undisturbed...hence a higher proportion are scattered and diffraction gets worse.
When doing landscape shots on a tripod and including some foreground interest, I was routinely stopping down to F14 and even F16 and F20 on my DX (APS) sensor cameras. This was mostly out of "making sure everything would be in focus" by extending the depth of field...playing safe.
If you look at any lens tests on APS sensor cameras its quite obvious from the MTF plots that diffraction starts to creep in and rob images of sharpness as low as F8. Beyond F11 it really starts to get destructive and F16-22 is simply a no-go zone. If you have a 12MP SLR, let alone a 16, 18 or 24MP SLR your lens will nowhere near out-resolve the sensor and will be the limiting factor in sharpness and resolution.
I did some tests with my own 12-24 lens and found that sharpness held up well to F11, then declined. I was keen to see if this limited my depth of field enough to prevent me getting sharp images with close foreground interest, while still retaining sharpness at infinity.
I was surprised to learn that with careful focusing I could easily get objects in focus from around a metre away to infinity at F11. That was more than enough in all but the most close-up of situations. To make sure I nail the focus I often shoot in manual focus and set the distance scale so I'm not wasting DOF by focusing beyond infinity. I often shift the focus point and use the focus indicator on both the close and distant subject to confirm focus, before shooting.
In this image the Lion was under a metre away and even at F9 both it and the house are in focus at 12mm focal length. The image is sharp and has good contrast.
On full frame cameras diffraction effects tend to kick in perhaps a stop or two smaller than on APS cameras and many better lenses hold out to F16, but of course there is less depth of field anyway than on an APS camera.
As a result of this understanding I never stop down unnecessarily now, try to optimise my DOF and get better image quality as a result. Give it a try.
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