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A small clarification of the data I gave:

The standard deviation of focussing of 150 mm focal length at f16 is 0.1 mm The standard deviation of focussing of 150 mm focal length at f5.6 is 0.03...

Good Brian, thanks for replying to the issue of printsize.

Concerning the issue of focussing: my standard deviation of focus position of the lens over a series of 20 times focussing on the 4x5...

Thanks Brian for your response. Let me set one thing straight: I developed all 4 formats films myself, they were all Provia 100F and they were developed with a computerized machine, the Jobo ATL 2000...

Ellis,

that's a good point: I only indicated that I used RAW as file format for the digital cameras, but not how I processed them. Neither did I include information on the color depth of the...

To give some short answers:

Ellis,

if you see the captions under the USAF charts: raw files were used of the digital cameras, so I did state that.

I used the 300D as a representative of a...

Recently I finished some experiments on the image quality and "real-life" resolution of four film formats (8x10, 4x5, 6x7cm and 35 mm) and 2 digital cameras (6.3 and 5 megapixel). I've given the...

Hello Ken,

Less than a year ago I replaced the groundglass in my Technika MT 2000 with a Bosscreen (a Dutch product). Being concerned about a possible focus shift I checked it with a large...

Hello Mark,

I had the same problem with the reflex viewer on a Horseman 6x9 camera and a 65 mm lens. The following solution worked very well: I bought a plexiglass magnifying glass with a focal...

David misinterpreted the test I described with rulers to measure distortion. This shows how hard it is to explain something in words, so let me clarify: the rulers are used to measure in the prints....

This is my way of working with unsharp maskes. When looking at prints from digital files I noticed that you often see contrast enhancement in the mid fine detail range. This can be seen at bounderies...

The super angulon 90mm xl is a very good lens indeed when looking at the specifications. http://www.schneideroptics.com/photography/large_format_lenses/super-angulon/ Only 0.5 % at most distortion....

Hello Guy,

I've tried the converter on a 150/5.6 sironar lens and found that the resolution drops by more than 50% (from 300 lines/mm to 120 lines/mm) and the contrast was slightly reduced in the...

This camera comes in brown artificial leather rather than black, it is a predecessor of the present models 45FA and HD. It does not have a reversible back, otherwise it is similar to the 45FA and...

Hi Frank,

this rollfilm holder is very high quality like the other backs of Horseman. I'm using it on a Horseman 45FA with Velvia and Tmax, both high resolution emulsions and find that flatness...

Paul,

at low light levels it starts at "0" and you have to wait about 4 or 5 seconds before it jumps to the correct reading. The light "loads" the circuitry and by pointing at a brighter area, you...