Pentax countdown..........

[dougpeterson]

I used a pair of Pentax 645s for years (pre autofocus versions)

They were ugly little buggers but felt great in the hand, very well balanced with superbly controlled mirror return and film advance was as smooth as it got.

Most importantly the lenses were superb, their wides were BETTER than anything Hassie or Mamiya had (but so did Contax and Bronica & Rollei- just at a higher price).
Pentax made world class optics, that was never questioned by anyone who used them, and there wasnt really a bad lens in their 645 line (such as hassies current H 35).

If the 645D gets out of japan, the lenses will not be an issue, they will be the strong point.

I've never once shot with a Pentax lens. So this is more a generalized point.

How a lens performs with full frame medium format film and how that lens performs with a 6 micron 1.3x crop sensor are only mostly related. I've tested several lenses that I was told were excellent that were mid-pack at best.

Chromatic aberration in my experience is often more pronounced on digital systems than film (post processing lens correction can help with this a lot, but it's best if it's not there to start with) and 6 microns can be very demanding on resolving power.

Hopefully if/when it becomes available whoever is distributing it will be smart enough to get it in the hands of guys like Guy and Jack who have a lot of experience testing.

Doug Peterson (e-mail Me)
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[monza]

Hopefully if/when it becomes available whoever is distributing it will be smart enough to get it in the hands of guys like Guy and Jack who have a lot of experience testing.

Agreed.

I'm most interested in seeing the difference between Pentax 14 bit and the 16 bit of the higher end MF systems.

 

[carstenw]

There is some question about the 16 bits in at least some MF cameras. There were some threads here and more on LL about that. IIRC the ADC doesn't always handle more than 14 bits, and the lower bits can contain mostly noise anyway. There is some guy (who I had a run-in with, but who seems generally very knowledgeable about it) who wrote about this.

In short, I am not sure that there is actually a 14-bit/16-bit difference in real life.

 

[douglasf13]

Interesting post about 16bit MFD: http://www.fredmiranda.com/forum/topic/847088/2?keyword=x#7908771

 

[Guy Mancuso]

I've never once shot with a Pentax lens. So this is more a generalized point.

How a lens performs with full frame medium format film and how that lens performs with a 6 micron 1.3x crop sensor are only mostly related. I've tested several lenses that I was told were excellent that were mid-pack at best.

Chromatic aberration in my experience is often more pronounced on digital systems than film (post processing lens correction can help with this a lot, but it's best if it's not there to start with) and 6 microns can be very demanding on resolving power.

Hopefully if/when it becomes available whoever is distributing it will be smart enough to get it in the hands of guys like Guy and Jack who have a lot of experience testing.

Doug Peterson (e-mail Me)
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Thanks Doug the bottom line general rule of thumb is a 9 micron sensor would be more forgiving on lens resolution than a 6 micron. So as we keep dipping down it is going to take some better performance from the lenses. So some of the older glass out there may have some issues just like some old Hassy's and Mamiya glass when it comes to these new breeds of 40 mpx sensors.
I admit this Pentax is interesting for sure and maybe a good way to get in but somewhere along the line there is a catch to this system and we have to see what it is. Like to get my hands on it and I need to go read about it more for sure. One thing that Leica keeps marketing is this lens correction built in so no special raw processing software to process. So if that is the case it has been out since November and it is March now and no profiles for it. There is something to be said for proprietary software it's built for your cam and draws the most from those files. What is Pentax going to use are they going to depend on Aperture or LR.

There is marketing and than there is reality. There are two sides to every coin, two sides to every story and damn it takes two to tango. Enough analogies we need facts. :ROTFL::ROTFL::ROTFL:

Steven would be proud, sound just like a attorney. LOL

 

[stephengilbert]

That's "Stephen."

 

[Terry]

That's "Stephen."

What were you expecting ?? :ROTFL::ROTFL:

 

[dougpeterson]

Agreed.

I'm most interested in seeing the difference between Pentax 14 bit and the 16 bit of the higher end MF systems.

In short, I am not sure that there is actually a 14-bit/16-bit difference in real life.

Interesting post about 16bit MFD: http://www.fredmiranda.com/forum/topic/847088/2?keyword=x#7908771

Don't buy that BS. The files may be 16 bits, but that's just interpolation from the 12-bit AD converters. In fact, no MDFB amplifier/AD chain comes even close to the signal quality of D3/D3s/D3x or the Canon counterparts. In fact, pixel for pixel even the P65+ is worse than my lowly "toycam" - the Nikon D40. The only thing that the P65+ has got in its favour here is a base ISO of just over 40, an almost 6x higher sensor area, and a massive amount of pixels. Measured for pixel quality and colour accuracy it's quite a lot worse than even the worst entry-level DSLR today. It just beats this by piling on area and pixels. The best MDFB in existence isn't in the least hindered or kept down by a 12-bit converison readout.

O boy. Where do I start?

1) The A/D convertor in a Phase One back is 16-bit at the hardware level. Whether, by itself, it produces accurate data in the 15th and 16th bit I have no idea because I'm not a PHD. However, it is, for sure, 16-bit hardware - not 12-bit hardware stored as 16-bit data.

2) The entire image chain is important here:
Lens coating > lens > aperture/shutter > IR filter > microlenses > sensor pixel well > sensor readout > sensor-to-convertor path > A/D convertor > raw file > black calibration > characteristic curve > demosaic > ICC Profile > deconvolution > noise reduction > sharpening

In particular the black calibration data and noise reduction is incredibly important to producing natural, smooth, color accurate data in the highlights and shadows. If you know the exact kind of noise a system produces and you also sample that noise very carefully (black frame) and include that data in the raw file then when you go to reduce that noise the result is much much better than generic noise reduction. This is roughly similar to the method that the new Google phone uses to reduce the background noise by having one measurement with the signal and background (the exposure) and one measurement with just the background (the dark frame).

The point being that the statement that the P65+ has worse per pixel quality than a D40 is just absolute garbage. It surely must be based on something (the guy seems very intelligent), but it surely is not based on processing raw files from each.

A 65+ has the highest pixel quality (specifically DR and color) of any system I've ever used.

3) It's always tempting to reduce quality down to a single number and this goes for A/D convertors as well. Knowing the bit-depth of the A/D convertor used in a camera might indicate how much that company is prioritizing component-cost and speed compared to absolute image quality and it establishes a maximum possible quality level. But only the real world raw files will tell you what the actual resulting quality is.

Doug Peterson (e-mail Me)
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[dougpeterson]

That's "Stephen."

I wouldn't take too much offense given the constant swapping of THEIR and THERE

 

[David K]

Irrespective of how the camera actually performs it does seem to establish that a number of features that MF users have been asking for can, in fact, be delivered. Without driving up costs prohibitively. Just looked in my gear cabinet and find that I still have my Pentax 645 kit and lenses. Maybe they're now worth more than the cost of a paperweight

 

[Guy Mancuso]

I wouldn't take too much offense given the constant swapping of THEIR and THERE

If I EVER get this correct than it ain't me posting.

 

[stephengilbert]

To each his own. Guy's a photographer; I'm a speller.

 

[tetsrfun]

This may be a re-post but this site has more photos of the inside "bits" including the focusing screen showing the AF points.

http://www.fareastgizmos.com/digita...e_top_of_mediumformat_digital_slr_cameras.php

Steve

 

[monza]

I've been trying to compare to the Mamiya DM22 since it's the closest similar camera (currently under $10k for a two lens kit - 80 and 55mm), but can't seem to find the pixel size, does anyone know? The sensor is 20% bigger.

 

[etrigan63]

I just read that and even I have a couple of nits to pick:

Thanks to approximately 40 effective megapixels, it assures a wide dynamic range to faithfully reproduce the prevailing ambience and the sense of depth in super-high-resolution images that are rich in gradation and truthful in texture description.

Since when does the number of pixels affect the dynamic range of a sensor? Granted, more pixels = ability to capture more data, but it's my understanding that pixel well size is a greater determinant of DR than pixel count.

A newly designed shutter unit with a top shutter speed of 1/4000 second that can withstand as many as 50,000 shutter releases.

50,000 shutter releases? Is that a typo? Sounds like a pretty short active life to me. I'd burn it out in a little over a year.

Still the camera brings lots features from 35mm DSLRs up to medium format digital. I await to see the engineering responses from the established MFD brands.Their first reaction will be denial. All corporations do it.

Will this entry spur Nikon and Canon to jump into this market as well? Food for thought.

 

[David K]

50,000 shutter releases? Is that a typo? Sounds like a pretty short active life to me. I'd burn it out in a little over a year.

Boy, I'm feeling like a slacker now... That's a lot of MF shooting you're doing there Carlos.

 

[etrigan63]

Sorry David, I guess I wasn't clear. With my Nikon I shoot about 40K photos in a year. I shoot ballet which is just like shooting sports only they are dressed prettier and the lights are lower.

Assuming I would keep that up with an MFD camera, I would cook through one in about two years.

 

[douglasf13]

O boy. Where do I start?

__________________

Unfortunately, this becomes a matter of who to believe. FWIW, "theSuede" is a scientist that is actually employed by a company in this field. I've yet to come across someone on any forum more legitimate or knowledgeable than him, but ymmv.

 

[tetsrfun]

Interesting post about 16bit MFD: http://www.fredmiranda.com/forum/topic/847088/2?keyword=x#7908771

Thanks for the link...

Steve

 

[Jorgen Udvang]

I've been trying to compare to the Mamiya DM22 since it's the closest similar camera (currently under $10k for a two lens kit - 80 and 55mm), but can't seem to find the pixel size, does anyone know? The sensor is 20% bigger.

Apart from the price, I can't really see many similarities. The Mamiya has half the number of pixels and 2 stops slower max ISO. In addition, no weather sealing, lower resolution LCD and presumably a less sophisticated AF system. While I'm sure the Mamiya is a good camera, the specs indicate that it's assembled from parts they found in the bargain basement.

Another big advantage with the Pentax is the dual SD cards that will go into the slot of most current laptop computers (much faster download than with external units) and allows for RAW plus jpeg on separate cards. In my case, that means that the client can have jpegs the second the shooting is completed, or even earlier, during the shoot.