[Ian Stuart Forsyth]

For shots across formats, the lens design differences come from the numerical aperture differences. A 65mm f/5.6 on a 4x5 camera has the same FoV and DoF as an 11mm f/1.0 lens on APS-C. Needless to say, it's a lot easier to design a really sharp f/5.6 lens than a really sharp f/1.0 lens, especially if the APS-C lens must be retrofocus design to handle the registration distance

There is also the enlargement factor when you start looking at the differences between formats, take the 8x10 camera for a smaller format to be displayed at the same size as that 8x10 negative it would need to be enlarged a deal to match that size. So if both lenses are built to the same standard any of those manufacturing and design flaws will be also enlarged more and thus you will see those more pronounce in the smaller format whereas with the 8x10 you would never notice them.

With a larger format the lenses can be designed more loosie goosy with more emphasis on other IQ factors other than resolution while retaining good resolution.

[Digitalis]

With a larger format the lenses can be designed more loosie goosy with more emphasis on other IQ factors other than resolution while retaining good resolution.

Present day large format lenses are manufactured to standards that are equal to if not superior to common 35mm lenses, and are capable of maintaining average resolutions above 70lp/mm @ MTF 20% across the 8X10 frame. The standard lens for 8X10 format is 300mm*, roughly equivalent to 50mm in 35mm terms. It is a lot easier to design a 300mm apochromatic lens than an apochromatic 50mm lens - which have only been available in consumer markets in the past decade.

So if both lenses are built to the same standard any of those manufacturing and design flaws will be also enlarged more and thus you will see those more pronounce in the smaller format whereas with the 8x10 you would never notice them.

This is still the key advantage of larger formats, an average lens from 1928 on 8X10 format can easily outperform a modern apochromatic 35mm lens Designed in 2015 at an 8X10 print size. Though this presumes the printing methods and quality are exactly the same.



* Though of course each photographer has their own individual preferences for what is their normal lens. The main reason for this variation among normal primes is how large the image circle the lens projects which controls the degree of which one can employ camera movements. Personally I use a Schneider 240mm APO-Sironar-S which is roughly a 40mm equivalent in 35mm terms, it allows a for moderate degree of movements with extremely high resolution though there is a penalty of diminished optical performance when extreme movements are employed. Another consideration for large format lenses is the back focus of the lens: the vast majority of normal primes need approximately 300mm of bellows extension to allow for infinity focus, some lenses need significantly less bellows extension.

Medium format has a lot to gain from mirrorless. Pentax should stay ovf, its in the name. I had a vision of a medium format GR though. Strange and beautiful beast it was ;-)

What's the point, now that it's no longer possible to use any kind of focusing aid (e.g., split screen prismatic focusing screen) that way? Pentax doesn't even call "focusing screens" by that name anymore. All the optical viewfinder is good for is to see what the camera's pointing at.

[photoptimist]

All the optical viewfinder is good for is to see what the camera's pointing at.

And that's a lot better than what any EVF can do:

The OVF shows the scene at the full dynamic range of the human eye, not the restricted DR of the EVF screen and sensor. (From measurements on the K-1, it's at least 18-20 EV of DR)

The OVF shows the realtime scene with none of the lag created by shutter speed delays, sensor frame rate delays, image processing delays, and graphics subsystem display frame rate delays.

The OVF shows the scene without consuming battery power, heating the sensor, or waiting for the camera to boot-up.

And that's a lot better than what any EVF can do:

The OVF shows the scene at the full dynamic range of the human eye, not the restricted DR of the EVF screen and sensor. (From measurements on the K-1, it's at least 18-20 EV of DR)

The OVF shows the realtime scene with none of the lag created by shutter speed delays, sensor frame rate delays, image processing delays, and graphics subsystem display frame rate delays.

The OVF shows the scene without consuming battery power, heating the sensor, or waiting for the camera to boot-up.

No argument from me! I only wish it worked better.

[surfar]

Well not quite 75mp,but strong indications of R5and6 are coming.

45 and 20mp respectively reasonably fast at 12fps mechanical and 20fps electronic.Deep buffers and the video specs indicated could be not quite what arrives.

Confirmation likely in 2-3weeks.

[pinholecam]

I'd rather use that 75mp divided into +2/0/-2 ev pixels for a 25mp shot that has that much wider DR.


I really like 24mp on my Sony A7 and to me, thats the ideal amount of pixels for most uses (printing up to A3 for me)
Easier on the technique (ie. shake), easier on lens weaknesses (eg. edge resolution), faster to process and store.
36mp on my K1 has been ok, with some advantage in resolution and chance to take advantage to downsize an image, but I do not think its as balanced as 24mp for all the aspects listed above.

75mp will just be ridiculous overkill for me and I will not willingly buy such a camera unless its the only option on the market.

[KiloHotelphoto]

Well not quite 75mp,but strong indications of R5and6 are coming.

45 and 20mp respectively reasonably fast at 12fps mechanical and 20fps electronic.Deep buffers and the video specs indicated could be not quite what arrives.

Confirmation likely in 2-3weeks.

I'm still holding out on the 75-83mp body, I'm looking to upgrade my 5dsr.

The rumored specs of the R5 look good 45mp 12fps but I'm hoping for the high megapixel with 5-7fps dual CFexpress cards. This along with my 1DX2 will make for a great wildlife combo.

[surfar]

I'm still holding out on the 75-83mp body, I'm looking to upgrade my 5dsr.

The rumored specs of the R5 look good 45mp 12fps but I'm hoping for the high megapixel with 5-7fps dual CFexpress cards. This along with my 1DX2 will make for a great wildlife combo.

The "RS" 82mp may happen too.....there were strong rumours about it and 2 others,the 2 others have taken top rumour talk just lately?

Some nice lens patents are happening too,all just a matter of time.

February should reveal a few things.