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Forum: Pentax Medium Format 10-29-2017, 03:08 AM  
645z color rendering I need help
Posted By Kolor-Pikker
Replies: 21
Views: 970
Try using this 645Z profile made courtesy by Torger, a member of GetDPI: Dropbox - dcamprof-v0104-pentax-645z-neutral.dcp
I find it gives me really nice results in many cases, except HDRs, in which case Adobe Standard is preferable to avoid artifacts.
Forum: Pentax Medium Format 07-11-2017, 12:52 AM  
exposure range for 645z
Posted By Kolor-Pikker
Replies: 10
Views: 741
It's a bit complicated, an 8-bit jpeg can show high dynamic range without actually being able to store all of it, by way of compression, whether it be highlight/shadow recovery or another method. So each physical stop on-screen is represented by less bits than are required for them to be considered "lossless", however if you try to edit such an image tonally, it will immediately break apart and cause posterization. JPEG is a delivery format, simple as that.

The issue with the 645Z is that preview images or minimally processed jpegs do a terrible job of showing what the sensor is capable of, because most of its dynamic range is biased into the shadows, the histogram you see in-camera maybe represents only the top 2/3rds of your available latitude.
Converting straight into a jpeg without performing any shadow recovery will just throw away most of the dynamic range, as data near the extremes becomes regularized to "fit" the new data constraints.
Forum: Pentax Medium Format 06-21-2017, 12:09 PM  
New 645 lenses
Posted By Kolor-Pikker
Replies: 16
Views: 1,673
Pentax is in a bit of a pickle right now tending to three different sensor formats, and chose to dial down their medium format efforts to cope with full-frame demand.

At this point in time we really can't do much but put together wish-lists and speculate on what they're going to do, but I really do wish they'd hurry up, the 645 system is capable of so much and is being stymied by a lack of world-class lenses to get it to really kick ass.

25mm discontinued? Fine, but make something better like a tilt/shift next time, or go slightly wider not to draw comparisons to the 28-45.
No 100 or 110mm f2 lens. There really needs to be a fast, but not too long portrait lens.
No modernized zooms. The 45-80 and 80-160 are nice, but at f/4.5 they're way too slow to use effectively without stabilization and could be sharper. They ought to extend the focal range of the telephoto to at least 200mmbas well, perhaps make a 45-100mm and 100-200mm zoom? Seems like a much more useful range combination to me.
And of course there is nothing with leaf shutters, maybe that's just a limitation of the camera itself and it would take a new redesign to implement, but going forward it would be nice if they had at least a couple of lenses with them for those people who do upgrade.
Forum: Pentax Medium Format 06-15-2017, 01:32 AM  
25mm vs 28-45mm comparison on 645Z
Posted By Kolor-Pikker
Replies: 29
Views: 2,404
It's when the focus ring is electronically coupled to the lens, so when you turn it, you move an encoder than sends a signal to the camera, which in turn makes the autofocus motor focus the lens. Depending on how it's implemented, focusing action may feel disconnected or floaty from the actual input, and of course you can't focus at all with the camera turned off, which presents an issue when you want to adapt the lens to another system that can't deliver power to the lens.
Forum: Pentax Medium Format 06-14-2017, 02:03 AM  
25mm vs 28-45mm comparison on 645Z
Posted By Kolor-Pikker
Replies: 29
Views: 2,404
As you get wider, each additional mm adds a more significant amount of FoV, so going from 25->23mm is a big difference. Of course the GFX is also a mirrorless camera, so it has the advantage when it comes to WA lenses, in terms of size, weight, ease of design, etc. Even if Pentax comes out with something to compete on a technical level (also a 23mm f/4 for example), it'll still end up being bigger and more expensive.
Forum: Pentax Medium Format 05-21-2017, 01:56 AM  
Pentax 645 A 150 or the A 120 Macro
Posted By Kolor-Pikker
Replies: 9
Views: 733
With both lenses at f/4 the 150mm still renders more pleasing blur imo. I don't often shoot the 150mm wide open simply because it's a tad too soft for my taste, but it does hold equal footing with the macro at f/5.6 and down.
I'm not sure of the extent of the differences between the A and FA past aperture, but I don't think it should amount to that much.
Forum: Pentax Medium Format 05-20-2017, 09:53 AM  
Pentax 645 A 150 or the A 120 Macro
Posted By Kolor-Pikker
Replies: 9
Views: 733
I have the FA versions of both these lenses and really do prefer the 150mm for portraiture, the weight doesn't seem like a big difference, but the macro is quite a bit more... sluggish-feeling than the 150 I'd say?
It's more front-heavy, so you do feel the weight on there. It also has at least twice the focus throw, so you'll really be working that focus ring.
Forum: Pentax Medium Format 05-18-2017, 05:13 AM  
to Flash or not to Flash for portraits? and a question blurb on lens preferance
Posted By Kolor-Pikker
Replies: 15
Views: 1,154
Assuming it's mostly going to be outdoors at low ISOs, I think that you can do without flash. Fill is preferable on cameras that get noisy on back-lit subjects, you would have to do horribly for the Z to buckle.

Unfortunately I only have experience with studio flash. As far as I'm aware, most advanced users of flash fashion a chute that they can slide up/down that controls the amount of directional light the flash gives off.

I've heard that the Pentax LS lens shutters need to be cocked after every exposure, so it might put a hamper on your experience, but at 1/125th FP sync you're not going to be over-powering the sun without them. It's probably not worth it trying to go this route, at least I wouldn't.

If you want to try flash, that's fine, but I'm not certain it'll be necessary. It all depends on where the photos will end up and at what size, for a photo album the Z has enough leeway in post for you to fill and shape the light as much as you want in post without worrying about the integrity of the image.
I wouldn't try it if I were using any kind of Canon, but something on the level of the A7R2, D810, and similar, you can add fill in post without ruining the image unless there's like 5 stops difference, in which case you chose a poor spot for the photo in the first place.
Forum: Pentax Medium Format 04-17-2017, 03:15 AM  
Bye bye GFX - back to 645z
Posted By Kolor-Pikker
Replies: 28
Views: 3,202
I can certainly see this as a polarizing issue, as the use cases for an OVF and Live View or EVF are beneficial for different types of photography, and invariably some people might try and convince themselves that stepping out of their comfort zone might be worth it for some extra features.
Forum: Pentax Medium Format 03-22-2017, 08:55 AM  
DP Review casts doubts on the 44x33 sensor
Posted By Kolor-Pikker
Replies: 46
Views: 3,375
Woah there! someone could get an aneurysm with words like that around here. It's refreshing to see the Walmart of photography websites taking information any competent photographer already knew and spinning it into a new source of renewable energy.
Forum: Pentax Medium Format 03-19-2017, 04:18 AM  
How often do you use your D or Z handheld?
Posted By Kolor-Pikker
Replies: 36
Views: 2,597
The D I used to use pretty much only on a tripod in the studio, so I have almost no "normal" photos where I just used it handheld unless I was messing about. The 645Z is still a bit slow and clunky compared to the latest DSLRs, but there's nothing stopping you from using it how you want, coming from the equally-clunky 5Dmk2 I don't feel like I'm missing anything handling-wise.

When going outside of the studio I take the tripod maybe only 5% of the time when I have something specific in mind and know for sure that I'm going to need it, like nightscapes. You need at least 2x your focal length in shutter speed if you want to ensure good sharpness hand-held, so with the 55mm it's 1/125th and with the 150mm I go for 1/250th to start.

I would probably consider a monopod for general-purpose photography, because you'd otherwise need a medium-size tripod like a Gitzo 3 systematic to hold one of these cameras perfectly still, and that's a hassle even with a shoulder sling.
Forum: Pentax Medium Format 03-18-2017, 05:06 AM  
A plan for Pentax MF going forward
Posted By Kolor-Pikker
Replies: 34
Views: 2,686
I think this to be so as well. Before the GFX and X1D, I said here that Pentax could be fine focusing on 33x44, if it meant better optimization and size reduction of lenses, but now things have changed quite a bit. Pentax with their inherently large mirror box are limited what they can do regardless of sensor size, and the average person who looks at specs more than anything will probably wonder why they would pick a significantly larger camera just for an optical viewfinder, considering many MF photographers focus on using a magnified view on tripod.

At this point, size can be an advantage, since Hasselblad and Fuji have nowhere up to go by design, while the Pentax 645 is still a 645 mechanically. As shown here before, there is a huge amount of dead space inside of the camera even if not taking into account the actual mechanics, so a 645Z mkII could not only house a bigger sensor, but be made smaller at the same time. Just take a look at where the Ф mark is on the top of the camera - the sensor is about half-way inside of the camera body! popping out the tape measure, there's 4cm to the rear controls and 5cm to the point behind the LCD screen. Considering the camera is ~12cm long in total, one could save about 1/4 of the camera's size even without touching anything else. Shave the back off a bit or shift the whole reflex aspect of the camera rearwards, moving the SD card slot to the grip as in most SLRs, which would then let the connectors go in a line and let you keep the second tripod mount.

Even if it means less compatibility with the 28-45mm, they could just add in a crop mode as Sony does with their cameras, at 100mp the pixel density would still be greater when cropped down to a virtual 33x44mm, so you're not really losing anything by going with a bigger sensor no matter how you look at it.
Forum: Pentax Medium Format 03-17-2017, 01:39 AM  
Highlight range in newer MF sensors, real world experience
Posted By Kolor-Pikker
Replies: 11
Views: 770
I should add that while the extra sensor tech is nice, it's by far not the primary reason for upgrading, mine was actually purely to get Live View - that 16x magnification is wonderful. However, it bacame apparent as I began to handle to camera that it really does handle like a big DSLR; everything is just fast and works, no waiting 3-5 seconds for the buffer to clear or preview the image, burst shooting is viable, low light is never a reason to put the camera back in the bag, etc. It's an all-round better system looking at nearly every aspect of it.
Forum: Pentax Medium Format 03-15-2017, 01:03 PM  
Fuji GFX useage compared to 645Z
Posted By Kolor-Pikker
Replies: 51
Views: 5,268
Hmm, shame about people's impressions of the camera, Fuji had the right idea on many points, but I guess there's a first time for everything. The 645D wasn't exactly a hot camera either, but it was all we had for entry-level MF digital at the time.

I still want Pentax to cover what remains of the 645's weak points, namely the lack of a modern 45mm, no replacement super-wide (preferably T/S), no really fast ~100mm portrait lens (like every other system has now), and a stabilized tele zoom in the range of 80-160mm or even -200mm if they can pull it off.
And all new lenses need to be stabilized if possible, it's desperately needed for medium format whenever you're off the tripod. Having to use 1/250th at 150mm seems like such a waste coming from small format where 1/160th would've been fine (on top of having to make do with slower apertures).
Forum: Pentax Medium Format 03-14-2017, 01:13 PM  
Highlight range in newer MF sensors, real world experience
Posted By Kolor-Pikker
Replies: 11
Views: 770
To give you a rough idea of what I mean, here's an image as it's better than trying to describe it, just a random hand-held snapshot of the street outside:

left is how the camera saw the scene, the right is processed to look how I saw it

And crops:

While I normally wouldn't care if something like those roof panels blew out, it does show that highlight recovery + extra exposure + curves makes the highlights look much smoother than what you get by default. Speaking of which, even though the roof was just at the edge of highlight warning, it can't be recovered past what you see. Even stuff not directly illuminated by the sun can be hard to made to look good, as too much recovery makes all the other highlights look bland as it compresses the highlight range. So IMO highlight recovery generally shouldn't be used unless it's complimented with +EV.

---------- Post added 03-14-17 at 11:37 PM ----------

I'm having a hard time finding an old image that has something blown out that isn't the sky or a reflection as it's hard to actually intentionally do so with this camera, but I did finally dig up an image where the far corner was blown out in one shot and not in the next.

There is a two-stop difference between the shots, the one on the right is just below clipping with no changes to exposure settings, while the one on the left is just above warning level with -100 highlights, and already the gray false colors rear their ugly head.

Forum: Pentax Medium Format 03-14-2017, 12:28 PM  
Highlight range in newer MF sensors, real world experience
Posted By Kolor-Pikker
Replies: 11
Views: 770
I just set up a custom Lightroom profile to automatically apply to all imported images, which has some increased contrast by default. Digital as you might have guessed by this point is the opposite of film, it's the highlights you want to be aware of, not shadows. As long as you find the noise levels tolerable, you can just keep pushing shadows as much as you want.

Really? For me it was always more close-cut than that. Even if you do try and recover highlights in Lightroom, it's not a very good result, usually you can do about 10 points into recovery, and past that it'll just start generating a gray false color instead of producing detail. Haven't tried Irident developer.
Forum: Pentax Medium Format 03-14-2017, 11:45 AM  
Highlight range in newer MF sensors, real world experience
Posted By Kolor-Pikker
Replies: 11
Views: 770
The Z is quite interesting in the way it handles dynamic range... well, rather than talking about the specifics of highlights, I'm typically interested in total usable DR, and then adapt the way I meter subjects based on how the camera is set up.
Back when I used to shoot Canon primarily, their cameras are set up with a fairly equal amount of recoverable range on either end, so my 5Dmk2 only had about 11.5 stops, but you also had about 1.5 on either end of your exposure, so you tended to ETTR (expose to the right), which meant the ideal exposure was with the highlights just clipping the in-camera histogram, even with contrast turned down in picture styles (remember, the jpeg preview is what determines the histogram in most cameras, including Pentax's).

The 645D was kind of similar, but as you noted it had less highlight range in exchange for more shadows, if the 5Dmk2 you can't push at all without getting noise, the D had at least a stop or two. The Z is actually further along in this direction, as it has practically NO highlight headroom - if you clip the highlights in the preview they're gone (although you get a more accurate reading in live-view than the preview), while also having a vastly deeper shadow range.

This is actually convenient for me for one simple reason - I don't have to guess how to expose the scene, I simply have to avoid clipping the highlights. I already know that the camera has nearly 15 stops of DR at ISO100, and I know that it's largely ISO-invariant, meaning I don't benefit much from increasing my ISO within a few stops of an "ideal" exposure, which in turn means I don't have to risk losing highlights or adding needless noise by shooting at a too-high ISO. Unlike the 5D2 or 645D, I have no reason at all to "nail" the exposure in-camera.

As long as you keep in mind that the Z's noise floor is far below visible levels at low ISO settings, and that you're essentially looking at your middle-highlight range in the preview, this basically sets you up to shape how you want the highlights to look in post and "recover" the rest of the scene. However it does make photos SOOC look terribly bland, without a good helping of curves, saturation and some clarity/sharpening.

Is it a step up though? I'd definitely say so; I've been hard pressed to find a case yet where shooting HDR came in practical use, even in scenes where I did think I needed it, I simply chose to recover one of the images instead of blending as the reduced noise simply wasn't worth wasting time to process. You might have a different acceptable limit for what you may consider "noisy" shadows, but even then, anything more than a simple 2-shot blend is overkill for the Z, unless you want to shoot light bulb filaments or something.

Regarding the other cameras? I think they'll largely be within a 5% performance margin of the 645Z, so really it depends on whether their system as a whole interests you more, maybe they have specific lenses or features you might see as being more important, like a central shutter or whatnot.
Forum: Pentax Medium Format 02-27-2017, 03:59 AM  
Horizon line detail: 645Z & 28-45, 120 macro, 45-85
Posted By Kolor-Pikker
Replies: 14
Views: 1,030
Technically speaking, the optimal aperture for the sensor, if going by pixel pitch, is about f/10, but in practice you can very likely get away with a lot more, if an increased DoF would create greater perceived sharpness at the cost of some fine detail.
You can test this for yourself by setting up for a shot and running though a range of apertures from say f/8 to f/22 and then printing out a series of crops as they would be at final print size to compare.
The camera locks the mirror up on it's own if you shoot with a 2s timer from LV, so there's no need to switch it on at all. Use the magnification in LV to set up focus either way, as AF systems are often fooled in backlight, and the Pentax is no exception.

I'm also going to mention this ahead of time, but if you run into an issue shooting HDR brackets with both shutter speed and aperture changing, go into camera menu #4 -> E-dial prog. -> page 2 and under "M" change the function of the green button to TvShift.
It seems really weird, but apparently this obscure function is what tells the camera which parameter it's allowed to change for the purpose of bracketing, as opposed to which shooting mode you're in. So even if you're in Tv on the dial, if Tv is set up with P as the green button function, it'll bracket as though you were in P. If you set it up as above, you'll bracket with shutter speed while in M on the dial.
The green button is otherwise fairly useful as it lets you temporarily meter using a different mode, so you can be in manual but quickly set the camera to what it thinks should be a good exposure.
Forum: Pentax Medium Format 01-23-2017, 08:20 AM  
Lens advice + questions
Posted By Kolor-Pikker
Replies: 9
Views: 953
You should look at areas where the Z could offer something unique compared to your DSLR rather than straight equivalence, that isn't to say you can't shoot sports or wildlife with it, but you will have to compromise in at least a couple of aspects. What you will not be able to do is expect the same kind of high-level performance at long distances; the AF is going to be slower, you will have to get closer, and the tolerances for getting a stable shot are higher - meaning higher shutter speeds than you're used to, despite having to deal with a slower aperture. That's why I still have my Canon.
Forum: Pentax Medium Format 12-01-2016, 12:12 PM  
Can next 645 digital be made less deep?
Posted By Kolor-Pikker
Replies: 20
Views: 1,944
A/D conversion is done on-sensor as with all modern CMOS sensors.
Circuitry-wise, digital cameras are positively dinosaur-class in terms of complexity and miniaturization, as modern smartphones pack much more power into a form-factor even the smallest of P&S cameras would be jealous of, and even then 90% of the phone is the display and battery.
Sure, the iPhone or similar push fewer pixels (120mp per second burst vs 154mp), but on the whole you'd think that with 50x the internal volume you could do better than that. Heat in compact cameras is only a problem when shooting video, and in the thinnest cameras like the Sony A7 series there isn't much that's complained about quite frankly.
Even if heavily reduced in size, the 645X or whatever would still be a bigger camera than either the 'Blad or Fuji, and those companies are comfortable enough about their designs to release them as a product. I doubt there'd be a cooling issue.

That, and more nose room to prevent smudges on the LCD!
Forum: Pentax Medium Format 12-01-2016, 07:06 AM  
Can next 645 digital be made less deep?
Posted By Kolor-Pikker
Replies: 20
Views: 1,944
Based on the distance from the sensor plane mark on the camera you can tell there's quite a bit of distance to the back, not even counting the LCD. That's where majority of the bulk can be saved, because everything from there to the mount is set in stone, you can't shorten the flange distance in any meaningful way unless you essentially create a new camera system and mount the lenses via adapter.
Shortening the back also wouldn't have any impact on the camera's ability to potentially support a bigger sensor.

While I remain skeptical of how well the Fuji will perform in practice, the proposed lens line seems much more in line with my needs, and if modern performance is guaranteed at any aperture, it'll be a no-brainer. Lenses before bodies and all.
Forum: Pentax Medium Format 10-21-2016, 06:24 AM  
Water-damaged 645Z: not covered by warranty?!?!
Posted By Kolor-Pikker
Replies: 63
Views: 4,596
Well, the camera has been actually tested in extreme conditions, so water damage is something of a freak accident if it does occur. Either way, practically no company will cover water damage for any kind of product, so it's not outrageous to expect this to happen.
Forum: Pentax Medium Format 10-06-2016, 01:33 AM  
How to Set up Camera Profiles on 645Z
Posted By Kolor-Pikker
Replies: 7
Views: 856
It's hard to find the latest ones (v0.10.4) unless you know the address:

IIRC top one is done strictly based off an X-rite color checker, plus version is manually tweaked to look better in some aspects. While I don't find them to be particularly accurate and require extra tweaking in post, they do indeed have nice colors.
Forum: Pentax Medium Format 09-26-2016, 07:32 AM  
Fuji mirrorless medium format.
Posted By Kolor-Pikker
Replies: 152
Views: 11,269
This makes sense, it would also explain why the mount looks so large compared to the sensor, and ties into the things they mentioned about allowing the lens to protrude into the body even further than the mount distance.

Sony's issue is that they utilized the same mount as their APS-C NEX cameras, to have compatibility across the whole mirrorless line, but the reason the NEX mount was so large in the first place was for this extra leeway.
Forum: Pentax Medium Format 09-26-2016, 04:05 AM  
Fuji mirrorless medium format.
Posted By Kolor-Pikker
Replies: 152
Views: 11,269
As compared to every MFD camera maker ever that stated they offered "16-bits" of color depth?

Photography as a whole arguably has the least BS attached compared to literally any other art or craft, because you don't have to take anyone's word for it, everything can be measured empirically and inspected visually.

In any case, what I *think* they meant to say was that they had to ensure that light stayed perpendicular, not that the short flange distance enabled it, but given the bad english all throughout the presentation and interviews, I'll chalk it up to as lost in translation.

Because 120mm is already equally feasible to manufacture using the same methods regardless of flange distance. Even with 70mm of empty space behind it, you've still got free space until you reach the nodal point, whereas with any lens shorter than that, this point would end up inside of the mirror box, unless you used a retrofocus design to project the IC far enough to clear the mirror.

A short flange distance is almost always of primary benefit to lenses wider than whatever's considered "normal" for the format. However, you still have to contend with the issue of symmetric lens designs being inappropriate for digital sensors, and not having very fast apertures, so some level of retrofocal projection has to be kept intact regardless.
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