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Forum: Pentax Medium Format 09-30-2020, 02:56 AM  
Pentax 645Z next model
Posted By Simen1
Replies: 199
Views: 13,331
I'm sure a 645Z replacement is in the planning. We just have to wait and see when and how.

I wish Pentax buys some insanely expensive 6x7 gazillion Mp CMOS-sensors and make a limited series of 67D cameras, and maybe even a modern AF prime to go with it. Schneider-Kreuznach may have some suitable optical formulas for license production.
Forum: Pentax News and Rumors 06-27-2020, 05:56 AM  
Lens Roadmap 2020 June
Posted By Simen1
Replies: 200
Views: 20,764
For the n'th time. Planned lenses being realized. No new plans. Why? Are they planning for a bigger surprise, keeping their cards closer, or reducing development of K-mount products?
Forum: Pentax Full Frame 04-24-2020, 04:52 AM  
4K vs K1
Posted By Simen1
Replies: 34
Views: 1,861
I cant agree. On the sensor, each pixel only consists of true scene data in a single color. The other two primary colors in that pixel dont have any true color information or resolving information. Its only interpolated from neigbouring pixels that have those colors resolved. Comparing bayer to the older foveon sensors that have three colors in each pixel, the bayer truly have less resolving power on the pixel level, due to this interpolation. Its also possible to explain mathematically.

On the display side its another story. Each pixel have 3 colors, but its not a uniform pixel where all colors are presented at the same whole area. Each color covers only 1/3 of the pixel area (usually) and their position are 1/3 pixel shifted relative to each other (usually). In other words, details on the pixel level are skewed somewhat. This is what causes color fringing on small b/w text on displays when not using windows with the correct clear view settings. Or similar technologies that try to compensate for the shifted position of the colors.

Ideally we should have foveon sensors capturing 3 colors in each pixel and then a display which have all three colors covering the whole area of each pixel.
Or alternatively, a bayer sensor with a display with a sub-pixel matching bayer pattern.
Forum: Pentax Full Frame 04-21-2020, 01:29 AM  
4K vs K1
Posted By Simen1
Replies: 34
Views: 1,861
Actually your 4K display has 8,5M pixels consisting of 3 color-pixels each. K1 has 36M pixels consisting of only 1 color pixel each. Its a different approach to counting pixels. On the pixel level its not so easy to just count and compare "resolution", due to bayer convertion, other processing and color pixel position on the screen. Just think of all the screen pixel layouts that exist and the Windows clear view function.

The basic message here is that a K1 suits a 4K screen just fine even if the pixel math is confusing.
Forum: Pentax SLR Lens Discussion 02-19-2020, 07:56 AM  
Macro lenses best for panorama stitching?
Posted By Simen1
Replies: 24
Views: 1,231
Note that distortion are measured as % of the image frame. If you choos longer focal lengths, and thus needs more photos to cover the scene, you will get less distortion in the final scene, even if the distortion per frame are the same.

Ideally you would choose the longest focal length lens you want to carry and stitch lots of images to fill the scene. Its heavy and lots of work, so limit the ambitions to something more managable.
Forum: Pentax SLR Lens Discussion 02-19-2020, 07:40 AM  
Pentax fa 20 2.8 OR Samyang 20 1.8 Or ?? your help pls ....
Posted By Simen1
Replies: 18
Views: 1,342
Sigma has a couple of AF lenses that might be considered: The 20mm f/1,8 and the 24mm f/1,8. I doubt you will find them new, so I assume you will have to find used ones.
Forum: Pentax Medium Format 06-01-2019, 01:29 PM  
Pentax D-6x7 series
Posted By Simen1
Replies: 14
Views: 1,168
Nope, I'm just a tech geek. Well, actually I shot one film on a Bronica 6x7 with a 80mm f/2,8 many years ago, but I wouldnt cont that as experience in terms of lenses. My focal length experience are mostly from Pentax APS-C and full frame digital cameras. Thats why I calculate the equivalences to get a feeling of use cases.
Forum: Pentax Medium Format 06-01-2019, 07:12 AM  
Pentax D-6x7 series
Posted By Simen1
Replies: 14
Views: 1,168
Yes, but why go for 6x7 if you can get the same light gathering ability with a 36x24mm frame and a high end lens? Thats why i proposed several lenses at 180mm (FF equivalent 85mm portrait lens). The 180/4 limited for lightweight, affordability and high resolution. The 180/4 macro because we need a macro lens in the line up and 180 is a propriate allround focal length for that and f/4 to keep the weight and size down. The 180/2,2 would be an extreme high end lens for those that already have a 100 foot yacht and want a lens with truly out of the ordinary light gathering ability. Its 85mm f/1,0 equivalent.

@tuco: I believe the 180mm lenses would do the job for the 165mm ones. Pentax cant have 100 lenses for that system. I had to cut down on something. I believe the list of 14 lenses are more then long enough, I just couldnt figure out where to cut more. The launch plan are also quite optimistic. I gave them something to streatch for. :) 180mm (85mm eqv) are on the wide end of portrait lenses. A 165mm (77mm eqv) are on the very vide end. Some prefer 135mm eqv for portraits and thats what the D-6x7 300/3,5 are for. (140mm f/1,6 eqv)

Maybe I should add a portrait zoom for the lineup? A lens for head, half and full body, with shallow enough depth of field. Some prefer a 70-200 f/2,8 for portraits and allround use on 36x24mm frame. A 150-400mm f/5,6 would do the same job on a D-6x7. Maybe even push it til f/5,0.
Forum: Pentax Medium Format 06-01-2019, 06:58 AM  
Pentax D-6x7 series
Posted By Simen1
Replies: 14
Views: 1,168
Great! :)

The reason I proposed f/5.6 is that a the existing 600 f/4 and even 800 f/4 are truly humongous heavyweight and must have cost insanely much. I doubt they made more then 20 of each. An updated higher resolution lower abberation optical formula would be even heavier and more expensive. I did not propose f/8 because of AF sensing becomes more difficult and diffraction may play a role in the future. The lens must have a long lifespan and be ready for higher resolution sensors at least a decade. 600/4 600/5,6 matches the light gathering ability of a 300mm f/2.8 on full frame, but at a much higher resolution. And lastly I believe strong tele is not a huge demand for a 6x7 system.

I thought out the lenses carefully, not in a hurry. :)

Oh well, and its time to reveal my personal favourites. If theese lenses become real I would want one large aperture wide angle for night/aurora landscape photo and one portrait lens. F/4 would be sufficient for me. So, I would go for the 75/2 WR for landscapes and the 180/4 Limited for portraits. In 36x24 terms it would equal 35mm f/0,9 and 84mm f/1,9. I might also consider to exchange the 75/2 for a 50/2,8 WR (23/1,3 equivelent).
Forum: Pentax Medium Format 06-01-2019, 03:49 AM  
Pentax D-6x7 series
Posted By Simen1
Replies: 14
Views: 1,168
I totally agree, but I believe D-6x7 will need higher resolution lenses with AF (and of course MF ring). Some lenses for daylight (the limited series) and some for shallow depth of field and night photography (the large aperture series). I also believe backwards compatibility is important, and that mirrorless short flange is the way to go.

The large aperture series should offer a significant aperture advantage over equivalent 24x36 full frame lens. I intentionally made the selection of tele lenses small because i believe 6x7 are about capturing more of the frame and have higher tolerance for cropping. Tele easily gets too heavy and expensive too.

Also leaf shutter is intentionally left out of the line up because I believe its not important. There are several ways to work around the fast flash sync problem. But it should be compatible with old leaf shutter lenses.

Yes, the 345 format will dissapear just like the APS-H format did. As far as I know all except one of the D-645 lenses supports full 645 frame. That makes me believe that Pentax already planned for a future full 645 frame camera and the death of 345.
Forum: Pentax Medium Format 05-30-2019, 09:03 AM  
Pentax D-6x7 series
Posted By Simen1
Replies: 14
Views: 1,168
Ok, I admit it at once. Its just a weat dream, but there are nothing wrong about dreaming. Especially about Pentax gear. Larger and larger sensors are available for camera producers. Some of the biggest today are Sony IMX 211 and 411. Other companies have even larger sensors, but highly specialized and extremely expensive. Who would be the first to launch a "mass" market 6x7 sensor? (at the price of a family car) Anyway, I have digged into the specs of the 6x7 lenses, full frame lenses and made a spreadsheet about what lenses I would suggest to go with such a system. Any thoughts? Which lenses would you pick?
Forum: Pentax News and Rumors 02-25-2019, 12:41 PM  
Ricoh Theta Z1
Posted By Simen1
Replies: 130
Views: 18,198
Great update, even if I wish it had 4K 60 fps too.

Just a couple of questions:
- Why not two square sensors? 3:2 must waste so much sensor area.
- Since its 3:2, are their longs sides alligned 90 degrees apart so each side covers slightly into the other hemisphere?
Forum: Pentax SLR Lens Discussion 11-04-2018, 09:36 AM  
40mm 2.8 XS discontinued in 2016 ?
Posted By Simen1
Replies: 10
Views: 1,159
Why should it be discontinued? It works fine with any newer K-mount camera. Even full frame. Its main advantages are lower price and shorter length compared to the 40mm limited. The limited have a different set of advantages. Two different products.
Forum: Pentax Film SLR Discussion 09-17-2018, 03:03 PM  
Poll: Pentax K-1F idea
Posted By Simen1
Replies: 37
Views: 2,158
I would buy if it costs <50$.
Forum: Pentax News and Rumors 08-25-2018, 01:36 PM  
K3ii replacement
Posted By Simen1
Replies: 2,451
Views: 209,740
Its unlikely, but not impossible. Pentax _may_ be the first or only to utilize such a sensor, but again unlikely. I believe several companies are able to make 2,75 micron pixels at APS-C size with high yield without stitching.
Forum: Pentax News and Rumors 08-25-2018, 08:30 AM  
K3ii replacement
Posted By Simen1
Replies: 2,451
Views: 209,740
Not impossible, just unlikely. If they go that route, I expect them to launch a high end APS-C lower resolution camera as well. One with 4K 60 fps video, high dynamic range and 10+ fps.
Forum: General Photography 08-23-2018, 02:37 PM  
Favourite Aspect Ratio
Posted By Simen1
Replies: 13
Views: 786
I don't have any favorite.
Forum: General Photography 08-23-2018, 01:02 PM  
New Nikon Mirrorless
Posted By Simen1
Replies: 61
Views: 3,199
With the high price, size and weight of the 35, 50, 24-70 and manual 58 I doubt they will sell many Z lenses. I believe the FTZ adapter will be very popular. Actually I believe it would not make much difference if they bundled and welded the FTZ adapter to the camera. That said, I cant stop dreaming of what the Pentax K-01 should have been (the lack of VF being the most serious issue). I hope Pentax understands the obvious benefits of not needing to develop another mount. Pentax should make at least one K-01 successor with EVF, maby even two. APS-C + FF.
Forum: Pentax DSLR Discussion 08-12-2018, 02:44 AM  
Why not APS-H ?
Posted By Simen1
Replies: 19
Views: 1,772
There should be sensors sizes for every need, but there should be some distance between sizes. I think Pentax nails it pretty well with

- 1/3 - 1/2,7" (Q)
- APS-C
- FF
- 645 (which will transition from 44x33 to 53x41 mm sooner or later, increasing the distance from FF)

In my opinion the 1,27x factor between FF and current 645 is a little small, and the factor between Q and APS-C is to large, but the latter is hard to change because of Q lenses image circle. Maybe they can fit one size in between.
Forum: Pentax SLR Lens Discussion 07-09-2018, 03:33 PM  
M 20 f4; prices? Alternatives?
Posted By Simen1
Replies: 56
Views: 3,090
I believe its roadmap neighbor "Large Aperture Wide-Angle Single Focus lens" will be the huge one. Probably 24mm f/1,4 or close to that.

I believe the ultra-wide angle will be smaller and have f/2,8 or smaller aperture.
Forum: Pentax SLR Lens Discussion 07-09-2018, 12:00 PM  
M 20 f4; prices? Alternatives?
Posted By Simen1
Replies: 56
Views: 3,090
I believe that is what the "Ultra wide-angle single focus lens" are in the roadmap. I will be disappointed if its huge.
Forum: Digital Processing, Software, and Printing 06-17-2018, 01:30 AM  
Did you leave Adobe? Where did you go?
Posted By Simen1
Replies: 116
Views: 8,346
I never got caught by Adobe and have bought many lenses for all I saved. I currently use Darktable, Rawtherapee and Faststone.
Forum: Pentax K-1 06-14-2018, 11:00 AM  
Rokinon 8mm lens with K-1
Posted By Simen1
Replies: 10
Views: 1,401
I have a Samyang 8mm with non removable hood, and a K-1, but I have never combined them. I did some research about the Samyang before I bought the K-1. The hood on the Samyang limits the image circle to a rectangle slightly larger then APS-C. When the hood is removed the image becomes almost circular with a diameter about 1,2-1,3x the diagonal of APS-C, depending on how much vignetting you feel are acceptable and what aperture you use. In other words somewhere in between APS-C and FF. If you prefer square crops it will be almost 1,5x a square crop from APS-C.

Anyway, I decides to buy a Zenitar 16mm f/2,8 to replace the Samyang, I just havent got my self to sell the Samyang yet.
Forum: Pentax DSLR Discussion 05-19-2018, 01:55 AM  
Would love to upgrade to the K1 but...
Posted By Simen1
Replies: 18
Views: 2,278
The KP is well above K-3 in noise performance because of in camera post processing. You can get more or less the same with K-3 and in computer post processing.

I believe the autofocus performance is the main problem here, not noise. The Tamron is quite slow to focus. A much faster alternative would be the Pentax DA 55-300 PLM, but that has 1-2 stops smaller aperture, so its not perfect for low lighting sports. I think the Sigma 70-200 HSM is a good compromise. f/2,8, and fast AF, although not as fast as the PLM. The Pentax D-FA 70-200 is even better but its very expensive.

My advice is selling the Tamron and buy a Sigma. Then push the ISO a bit more and post process the noise better.
Forum: Pentax SLR Lens Discussion 05-18-2018, 01:53 PM  
Best "cheap" lens.
Posted By Simen1
Replies: 38
Views: 2,896
M 50mm f/1,7
A 50mm f/1,7
F 50mm f/1,7
FA 50mm f/1,7
DA 50mm f/1,8

All of these are great, and AFAIK uses the same optical formula (except for a slight change of the aperture diaphragm in the DA), but there are improvements on functionality (aperture coupling and AF), coatings and changes to the exterior and mount.

I have the DA and a M 50mm f/1,4 which is said to be as sharp as the f/1,7 variety, but I always choose the DA before the M on my digital cameras. I think the 1000 NOK I paid for a new DA, was a bargain.
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