Pentax K3 III Monochrome

It appears that this may well be the subject of the Ricoh announcement schedule for tomorrow - an announcement appeared and was taken down very quickly, but one of the users over on the US forum captured a screengrab and has sourced images of the new adaptation of the K3III

Interesting as an addition to the Pentax line-up - quite Leica-esque

It certainly has the forums a-buzzing !

I still don't know how a monochrome sensor can produce better images than a colour sensor camera and a good bit of software on your computer, I am keen to learn

If it sells well for Pentax I am all for it.

I'm guessing it's the same sensor but without the Bayer colour filter so you'll get monochrome images with effectively pixel shift resolution with a single image not 4 consecutive images needed for a colour pixel shift image.

Mike

Here's a link to a Japanese Web page, Chrome can translate it:

link

Fascinating thread. I take the view of pschlute, 'If it sells well for Pentax I am all for it.' Yep, works for me.

I don't see the pixel-shift connection. My understanding is that a monochrome sensor is all about the grey shades. I understand that it will encourage folk to use yellow or green filters on the lenses like when shooting film.

But I still do not see how this will be an improvement on what we currently have. In Photoshop I can replicate any filter colour under the sun, and selectively too.

I am not knocking the new product, merely trying to understand it.

Follow the herd worked while there was a large market to sell to, as that market has changed/dwindled then the path (or paths) to take have to be chosen carefully and with a mind to what revenue can be generated from them. So far Ricoh has not only stayed with SLR's with mirrors but advanced them significantly with the K3 MkIII and this venture into Monochrome although seemingly quite narrow or "specialist" happens with the knowledge that there are many users with Pentax fit lenses, some with spare cash, and some with a longing to produce the best Black and White images they can, so maybe this innovation will bring a few new users and will surely have some existing users reaching for the credit card

I think the point is that for a single shot with the usual RGB filter in front of the light sensors, the light intensity and colour at each pixel position must be calculated as an average of surrounding pixels in order to get the contributions from all 3 colours (RGB). Pixel shift improves on this by taking successive images with different filter colours (RBG) at each position so the calculation at each pixel is from RG and B at the same position (i.e. not averaging over adjacent pixels). Removing the usual RGB filter also removes the need to average over adjacent pixels so has a similar effect to pixel shift but, of course, it's only for mono not colour. Importantly, though, it does not need multiple exposures for a single image so does not have the pixel-shift problem of subject movement between successive pixel-shifted shots. The overall effect will (should ) be better handling of grey shades than a single shot with RGB filter because of the absence of averaging. Whether most of us would notice the difference is another thing entirely...

Steve

Here's an interesting web page about the method and effects of the Bayer filter on resolution/sharpness.

link

I've compared non-pixel-shift vs pixel-shift of the same subject with my K-1 and the improvement in image sharpness is certainly visible. The RAW file size is nearly 4 times (46.7 MB vs. 173MB) the non-pixel-shift version even though the image dimension in pixels is the same at 7360 x 4912 pixels.

In fact the K-1's image sensor will actually have (7360 x 2) x (4912 x 2) light sensitive sensor elements with 4 being averaged together (1 red, 1 blue, 2 green (bayer) filtered sensor elements) to become a single non-pixel-shift pixel.

All a bit boggling!

Cheers
Mike

Thanks for the explanation Steve, I see the connection now.

So more accurate shades, and sharper images should be created by a monochrome camera.

Presumably the lack of the Bayer filter should have other benefits too, like a stop or two of better light gathering properties/high ISO performance ?

Thanks for that link, he explains it very well.


The increased size is because the raw file contains data from all 4 discrete captures. It is only when you open the file in compatible processing software that the magic of PS resolution occurs. If you try and process the file in non-compatible software, it either won't open, or will use only one of the 4 captures to process into an image.

Looks like the K-3 III Monochrome is real. DPR, still active a day after they were due to shut down, have posted an article. The price is a $200 premium over the original price of the standard model.

Shooting in monochrome works best IMHO if we shoot in mono, and to emulate that I have always set the camera to BW JPEG capture. This gives a different minset when shooting the images, rather than deciding afterwards what to do. The K3 III Monochrome takes that one step further and is great for mono shooters. The Leica Monochrome cameras are very expensive, so a more reasonably priced offering could be a real winner. A great idea and one that PU members asked for a long time ago.

Meanwhile, why is the resolution higher? All sensors are monochrome and it's the overlay of the Bayer filter that generates the colour information. Each dot in the image, so to speak, comprises four pixels. Remove the filter and each pixel gives information, increasing the resolution.

There is a video on YouTube by Matt Bishop testing it,

Someone, somewhere, is no doubt developing an AI plug-in for Photoshop that takes a mono image and adds colours to simulate that authentic, old-time, hand-coloured B&W photo look...

Steve