[Digitalis]

would guess that even a perfectly constructed lens has a theoretical resolution limit

Schneider and Rodenstock* both specify the pixel pitch suitable for use with their top of the line optics it is usually within the 5~7 µm range**. They also offer comprehensive charts on MTF, distortion characteristics, chromatic aberration and vignetting that allow for the true character of the lens to be known before you buy it. Pentax, Leica and Zeiss do not mention this limit - and I suspect they don't build lenses to suit sensor pixel pitches***, but Schneider and Rodenstock being top of the line cost-no-object lenses they can afford such excruciatingly high tolerances...and their prices show it.


* Angenieux also do this, their high performance cine lenses are built to neurotic tolerances - which explains why the median price for their lenses is around $20,000.

** there isn't anything inherently wrong with using a lens designed for a 7µm pixel pitch on a sensor with a 5µm pixel architecture. However the resulting will probability need adjustments for chromatic aberration - using lens with 9µm chromatic aberration on a 5 µm sensor will make the chromatic aberration more obvious than it would have been on a 7 µm sensor - and yes, Schneider and Rodenstock do control aberrations like that down to the micron level.

*** The Zeiss 50mm f/1.4 Otus and the Leica Summicron-M 50mm f/2 APO being a notable exceptions to this, which is rare in the world of 35mm optics.

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Last edited by Digitalis; 04-17-2014 at 06:00 PM.

[dtmateojr]

The A7R will resolve more detail but the 645Z will have a larger image. Resolving power is first and foremost dependent on pixel density. Image size (megapixel) is not equivalent to resolving power (resolution). And yes, the Q will outresolve both of them.

[normhead]

The A7R will resolve more detail but the 645Z will have a larger image. Resolving power is first and foremost dependent on pixel density. Image size (megapixel) is not equivalent to resolving power (resolution). And yes, the Q will outresolve both of them.

There's that old adage, "if you don't like your pictures move closer" I'm guessing a 645Z with a macro lens will seriously out resolve a Q with a standard lens if they both are pointed at the same test chart in such a way that the chart fills the frame on both cameras. I think you need to be a little more careful in defining the parameters of you assertions so folks understand exactly what you're talking about. It's not that I don't understand what you think you're saying, it's that I don't think you've stated it clearly enough so that someone who doesn't understand what you're talking about won't get confused.

I'm not sure what you mean by "larger image" either. The collection of bit and bytes that make up an image have no size information attached to them. 36 Mp on an FF is the same size as 36 Mp on an MF camera. How is one larger than the other? That definitely needs some clarification.

[dtmateojr]

There's that old adage, "if you don't like your pictures move closer" I'm guessing a 645Z with a macro lens will seriously out resolve a Q with a standard lens if they both are pointed at the same test chart in such a way that the chart fills the frame on both cameras. I think you need to be a little more careful in defining the parameters of you assertions so folks understand exactly what you're talking about. It's not that I don't understand what you think you're saying, it's that I don't think you've stated it clearly enough so that someone who doesn't understand what you're talking about won't get confused.

I'm not sure what you mean by "larger image" either. The collection of bit and bytes that make up an image have no size information attached to them. 36 Mp on an FF is the same size as 36 Mp on an MF camera. How is one larger than the other? That definitely needs some clarification.

A 50Mp image is larger than 36Mp. However 36Mp on a smaller sensor has a better sampling rate than 50Mp on a larger sensor. I'm not familiar with 645Z but the same concept can be applied to a K3 (24mp) vs D800 (36mp). Resolving power is affected by sampling rate. K3 has more resolving power than the D800 although the D800 has a larger image. A K5 and D800 have the same resolving power (same sampling rate). Photographers erroneously equate image size to resolution. They are not the same. The OP is correct in his confusion

[6BQ5]

..... The OP is correct in his confusion

Good one! Haha!
I think it was mentioned here that the target size of the displayed/printed image matters. Would it be fair to say that if my target is an 8"x10" print then the 645Z would have less resolving power than the FF Sony. Assume that the lens quality for both cameras is superb and a hair's width away from perfection.

[Hakusan]

The easiest way to think about this is a 50MP sensor can resolve finer details. If your 36MP print is resolving 100 line/mm, then a similar print from a 50MP sensor will be resolving 118 line/mm. You are get 18% greater resolution over a 36MP sensor (square root (50/36).

The difference between the 645D and 645Z in terms of resolution is 12%. If your current lenses work well on the 645D, they will work well on the 645Z. Even the lowly A series lenses.

[rfkiii]

you're forgetting one important factor - lenses. The Sony A7R with a good copy of the Calr Zeiss 50mm f/2 Makro planar would be roughly equal to the 645Z with an older film era 75mm f/2.8 - MF sensors don't strain lenses as much as smaller formats do. However if you put a newer Pentax Zeiss or schneider lens on the 645Z the equation tilts drastically in favor of the 645Z. A sensor is only as good as the lens you put in front of it.

Hi, the following question is probably a bit off-topic for this thread so my apologies.


I am a Canon and Nikon user who is considering cashing in his Nikon kit for the 645Z and as many lenses as the proceeds will buy which I will add to later as funds become available.


I am aware of the Pentax brand lens offerings and that the 25mm, the 55mm, and the 90mm are the most modern of the line-up since the intro of the 645D, but I am interested in what you have said about Pentax Zeiss and Schneider lenses. Could you expand upon these comments i.e. name a few specific lenses under Pentax Zeiss and Schneider brands that can used/adapted and I'll probably be able to extrapolate from there?


If you wish to be more expansive than I have asked for, that would appreciated as well.