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Forum: Pentax Medium Format
01-11-2018, 07:55 PM
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Hi Sarnian, I use the Mamiya 645 50mm shift on my 645z. This lens was produced/modified with a hasselblad mount, which via adapter fits onto the 645z. Infinity focus OK. These lenses sometimes show up on ebay.
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Forum: Sold Items
10-04-2015, 01:50 PM
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Hi,
Is your 25mm lens still available?
Thanks,
Philipp
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Forum: Pentax Medium Format
09-30-2015, 10:43 AM
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Hi Fotophil,
Regarding the Mamiya 645 50mm shift. There are some examples out there with Hasselblad mount. Easy to use on Pentax 645 via adapter. It achieves infinity focus without introduction of glass elements. I have been using mine on 645z with excellent results. The conversion was done by Zoerk in Germany I think.
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Forum: Pentax Medium Format
08-09-2015, 12:42 PM
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Ditto from me. A while back I had posted the same question elsewhere in the forum, with no resolution. Thanks Fogel70!
Pentax programmers please don't be so cryptic!!
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Forum: Pentax Medium Format
08-09-2015, 11:27 AM
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Hi Michael Biondo,
Thanks for posting your experience with the Hartblei. Unfortunately, this mirrors my experience exactly. There must be a large sample variation factor. On the 645z, the problems are even worse of course, as the sensor uses more of the outer image circle with attendant decreasing image quality.
I was considering sending my lens back for re-alignment, but your experience doesn't bode well.
Philipp
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Forum: Pentax Medium Format
04-12-2015, 05:18 PM
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PTGUI is very capable. I have stitched a lot of hand-held panos together by leaning myself up against something, and rotating the camera around my lens' point of of zero parallax. Your mileage will vary depending on how stable you are, and how forgiving your foreground is. Shooting something at a distance, with grass or dirt in the foreground is easy. Images which include structured foregrounds (furniture, grout lines, railings, etc.), combined with a wide lens, are less forgiving.
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Forum: Pentax Medium Format
04-12-2015, 02:16 PM
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Hi The Ether
Since the fixtures have some depth to them, I use a spherical head (older Manfrotto SPH 303), which would cause mis-alignments. 99% of the time I rotate around a fixed point. The only time I displace the camera horizontally and/or vertically in relation to the subject is if I'm dealing with a truly flat surface, like a large canvas, mural, or the like.
What's your experience?
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Forum: Pentax Medium Format
04-12-2015, 12:41 PM
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Hi MikeSF,
Thanks for your reply. I use PTGUI for all my stitching, and it does a great job blending even when the exposure varies from one frame to the next. I know because I've inadvertently bumped my dial to Av, instead of leaving it on M. I tried uploading a couple of images yesterday, but I can't find them on the Forum, so here is a link to some samples of what I do:
CONSTANT_APERTURE_AEB_THREAD_PTX_FORUM_2015_04_12
Varying exposures in a pano sequence can work if your subject is forgiving. But these fluorescent works are often installed in white box galleries. Smooth white walls leave no room for blending errors, and they are hard to fix.
Hi The Ether
Thanks for the heads-up regarding the limitations of both software, and flu-card. All exposure parameters and review of histogram would be done before entering tethered mode, so as long as I can control aperture and shutter speed from laptop or tablet, I think it will work.
Philipp
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Forum: Pentax Medium Format
04-11-2015, 04:17 PM
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Hi MIke SF,
Sorry if this is confusing. I need both a constant aperture, and a known set of shutter speeds for this to work. The two panos I've uploaded show no seams, because all image capture parameters per bracketed set of exposures are the same. This wouldn't be the case if the camera were responding to changing light levels in AV mode, depending on which part of the light work it was pointed at.
Uncle Vanya, your solution is the only workable one for controlling a DFA lens in this situation. Reviews state that Ricoh's tethering software works well. Thanks! I will order the software from B&H through this website.
Kolor-Pikker, for me the whole point of using AEB is is to ensure pixel-perfect alignment of a bracketed set of exposures. The DR of the 645z is great, but this work sometimes requires 4 - 5 exposures to retain highlight and shadow detail.
Why Pentax chose to design its AEB function this way is a mystery to me. Maintaining the same optical qualities (sharpness, DOF, bokeh, light fall-off) in a bracketed set is pretty important, especially in HDR panos as Royce mentioned.
Anyway, thank you all for your thoughtful input.
Philipp
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Forum: Pentax Medium Format
04-10-2015, 08:25 AM
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Thanks for your reply Royce. Good to know I'm not the only one who finds Pentax's AEB design to be at odds with most other manufacturer's designs. I guess I'll start a letter writing campaign to see if this flaw could be addressed in a firmware update.
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Forum: Pentax Medium Format
04-09-2015, 11:23 PM
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Hi Ole,
Thanks for your reply. I tried that, but as the lighting changes, the Av responds of course. I'm need to have a known set of shutter speeds at a constant aperture, regardless of varying light levels. I guess I'm going to have to stick with the older lenses, maybe find a 55mm A or adapt a 67 55mm.
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Forum: Pentax Medium Format
04-09-2015, 09:34 PM
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Hi All,
I'm late to this thread, brand new member to the forum.
Regarding the Hartblei 45mm super rotator, I purchased a new one eight years ago, and have used it on many different cameras. Mechanically it is ingeniously designed, and solid as a tank. Optically it is not a great performer. Lots of CA, curved plane of focus, soft in one corner. Perhaps the new ones are better, but make double sure it is the newer design. Many of the 45mm super rotators on ebay claim to be the digital version, but the lens groups appear to be exactly the same as the old ones. The only really sharp ones are those where Zeiss provided the glass, and hartblei the body. These sell upwards of $4K if you can find them.
I have had much better luck with a Zörkendörfer or Zoerk modified Mamiya 50mm shift lens (no tilt) made to fit Hasselblad. Every now and then you can find them on eBay. I recently purchased two copies for around $600 each, one went to a colleague. Very sharp, low CA mild barrel distortion easily corrected in ACR.
Agree with one of the posts mentioning use of a 45mm pentax 67 lens using a zoerk pro shift adapter. This is a pricey item somewhere around USD 2500 last time I checked.
Z
So, for the time being, the 50mm Mamiya/Hassy shift is it.
If tilt with longer focal lengths, or/and macro is your thing, check out Zork's multi focus system which employs enlarging lenses. It can also be used in conjunction with the Pro shift adapter.
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Forum: Pentax Medium Format
04-09-2015, 09:09 PM
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Hi All,
I'm new to the forum.
For the last year and a half I have been shooting 645D, and Z for last six months. I have ongoing work which requires shooting bracketed sequences of artworks containing light sources of varying intensities. These are shot from a solid tripod, using a cable release, AF disabled, constant aperture, while auto-bracketing the shutter speed. All is well when using A, FA, & 67 lenses, as I can set the aperture manually. But, when using the DFA 55 I can not figure out how to get the camera to shoot the sequence with a constant aperture. I get a proper bracket in terms of exposure values, but the shutter speed and aperture are varied according to the camera's logic. The only way I can work around this, is to bracket by hand, which can introduce camera movement.
Has anyone else encountered this, and more importantly, have you figured out a solution?
Thanks,
Philipp
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