120mm macro lens (70mm~)
Courtesy of The Flash Centre, Birmingham.
I've had hold of the new PhaseOne 6x4.5 camera for about a month now, and to be honest it's taken some getting used to.
The system is NOT designed to this sort of work - not by a LONG WAY - and when Kev and the guys at TFC asked me if I'd have the gear on loan to try and replicate some of my macro work I did make my reservations apparent.
My main concern was, and still is, the 120mm f4 macro lens. My usual focal length of choice is 180mm on an APS-C camera, and effective 270mm angle of view - and the Mamiya macro lens that couples to the PhaseOne only equates to around 75mm. This is WAY TOO SHORT and gives massive problems with its huge angle of view.
The main problems are, firstly the need to be very close to the subject in order to obtain close-up detail shots; and secondly, the wide angle of view leads to more depth of field, which plays holly hell with the backgrounds.
The published minimum focus distance for this lens is 1.3 feet, but I don't know where they were measuring from when they came up with that measurement - this image was shot at about 8" from the front lip of the lens hood.
Full techs are:
1/4sec @ f11, ISO 100
This is a 57.3Mb crop from a 92.8Mb original - so pretty hefty, but the lens angle of view and minimum focus distance precluded me from making the subject any larger in the frame - hence I've had to resort to cropping.
If only there was a 400mm macro! Mind you, 250mm would be a god-send....
The sensor was not in 100% perfect alignment with the main subject plain so there is a slight run-out on sharpness towards the wing tips, abdomen tip and the lower part of the frame in general.
The whole lens problem is a crying shame because the PhaseOne P30+ back is just astonishing in its performance.
With some of the other shots I've been doing I've come to the conclusion that the back has a huge Dynamic Range of at least 13.3 stops (measured with the spot meter on my trusty D2Xs).
The P30+ has an ISO operating range of 100 to 1600 and, although I always shoot at the lowest iso setting when doing macro work, it's nice to know what the higher settings look like.
Here's a 'peek' at the full range of iso - again all unsharpened native resolution. Take special note of the blacks in the hole and the cement in half shadow.
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For me iso test shots mean nothing unless I see them in context, so here is the full frame image - from a CapOnePro direct export 16bit TIFF 6496 x 4872 pixels, 181.1Mb. The crop area is indicated in red. |
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Now I can see a negligible difference between 100 and 200 iso - yes it's there but I'd have no problems with it at all. 400 iso is starting to show degradation in fine detail, and this degradation increases dramatically at 1600iso. I suppose it depends what your market place is - the 400 iso image could look better with some judicious processing, and do bare in mind that the file sizes are huge. This means that you could infact reduce the 8bit 92Mb files - down-sized by 40%, they'd look a lot better and still come in at above minimum spec for libraries like Alamy. But the potential sales from massive CLEAN images when all your competion is running on 21 - 25Mb 35mm format bodies are very high. So to maximise your image quality 100iso would be preferable as your standard iso setting.
MORE TO FOLLOW |
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