Cross platform equivalency

Started Apr 25, 2014 | Discussions thread
Rick Knepper
OP Rick Knepper Forum Pro • Posts: 16,327
Re: My ears were burning. ; -)

qianp2k wrote:

Great Bustard wrote:

Rick Knepper wrote:

FF > MF that is.

Yes this will concern a rumored Canon camera, not an actual one (at least for the moment).

I am pretty comfortable in my understanding that more MPs per given area results in more detail.

Let's say this rumored camera, casually referred to on this forum as the High Resolution Monster, has 51 MPs just like the Pentax 645Z.

Those same number of MPs will be laid out on .79x less area on Canon's FF sensor as opposed the Pentax sensor.

I have admitted in the past that I am fuzzy on cross platform equivalency but until now I have not been interested in anything but FF. The Pentax 645Z may change that.

Noise and DR aside, which set of 51 MPs will produce more detail, less detail or the same detail in the respective systems all other things being equal?

GB mentioned large pixel blur the other day so I am interested if that concept applies here in any way since the pixels on the Pentax sensor will be larger.

Anyone not familiar with the Pentax 645Z can catch up here:

The pros of the 645Z, $8499, 51 MPs. on a sensor larger than FF, weather sealed, 25 cross-type AF points, and wait for it.............. articulating LCD.

The cons: 3 fps.

Lenses for the system mostly look reasonably priced although you won't find any pity-fifty pricing. The MF>FF crop factor is .79 according to DPR.

Here we are:

In short, the resolution as a function of sensor size and pixel count can be summed up as follows:

For a given lens sharpness, the difference in resolution (lw/ph) between two systems will be between the ratio of the sensor heights (enlargement ratio) and the ratio of picture height in pixels (linear pixel density). The sharper the lens, the closer the balance will be to the ratio of linear pixel density, the less sharp the lens, the closer the balance will be to the enlargement ratio.

More specifically, the lenses for a 51 MP FF DSLR with the same AA filter as the 645Z will have to be 1.3x sharper than the lenses used on the 645Z to resolve as well.

What your guys' opinions on IQ in 645Z samples? Much better than D800E with Otus 55/1.4 or A7R with FE 55 at their respective full sizes?

Dang. I won't venture a guess on a comparison to a D800E or A7r with these two lenses, but the images at the link have more clarity at 16% mag than I have been able to wring from my D800 and lenses and my PPing. These have a realism I don't normally see from 35mm. To me, the second tree image has more of a 35mm look to it (or rather a look I am more familiar with) because it doesn't look as photo-realistic. I see some haloing in the image as well. The others are very nice.

I suppose it would help to know the lenses that are part of the capture.

-- hide signature --

Rick Knepper, photographer, shooting for pleasure. It is better to have It and not need It than need It and not have It. Various RAW comparisons at Link below. Includes 5D3 vs D800E (new uploads), 5D3 vs. 6D, Zeiss lenses etc.

 Rick Knepper's gear list:Rick Knepper's gear list
Pentax 645Z Canon EOS 5DS R Fujifilm GFX 50S Pentax smc D FA 645 55mm F2.8 AL (IF) SDM AW Pentax DA645 28-45mm F4.5 +8 more
Post (hide subjects) Posted by
(unknown member)
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow