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Forum: Pentax Medium Format
03-13-2011, 05:58 AM
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Thanks for info, Bob. I have the 16464k
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Forum: Pentax Medium Format
03-10-2011, 12:46 PM
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I think that it is not possible to build an adapter for R lenses: the distance from bayonet to focus plane
for Leicaflex is only 47mm, while for the 645 is 72, to great a difference.
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Forum: Pentax Medium Format
03-10-2011, 11:32 AM
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Dave, I suspect that the adapter available on eBay is suitable for the Visoflex 1 system
that is described in the following link
http://www.l-camera-forum.com/leica-wiki.de/images/3/31/Visoflex-I-BAL_VI-53-DY.pdf
My adapter is suitable for Visoflex 2 and 3 lenses. Complete description here
Visoflex I
65mm, 90mm, 135mm lenses all require a common focusing helicoid, while 200mm and longer go directly on the adapter as these were directly designed for Viso and have theyr own focusing helicoid.
The lenses can be used in auto exposure with aperture priority. The 65 and 200 have a ring to preset aperture, so you can focus full open and than close the diafragm in a "semi auto" mode.
Do you allready have Viso lenses?
Sergio
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Forum: Pentax Medium Format
03-10-2011, 10:34 AM
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Ron, I made this one using a 645 front cap, an aluminun ring to position a Leica bayonet,
"borrowed" from a type 2 Viso (only 6 screws). If you want, I can make a drawing.
DW, the adapter advertised on eBay is for m39 Visoflex lenses, that should also be usable.
ogl, full size samples of the images posted below are available on the "view all sizes"page
on Flickr (1&3 iso 1000, 2 iso 200)
Gurtch, as Lager says in his Leica book(so a Leica expert told me), Visoflex lenses are derived from large format designs, and have a very wide image circle. I see no vignetting, and just a slight resolution loss on border of images, (with resolution charts) but nothing that cannot be accepted
from an old Leica lens, and yes, 65mm is the shortest that can be used.
Sergio
_IGP5124 by sergio lovisolo, on Flickr
_IGP0374 by sergio lovisolo, on Flickr
_IGP5114 by sergio lovisolo, on Flickr
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Forum: Pentax Medium Format
03-09-2011, 02:47 PM
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If someone likes the particular look of images shoot with old Visoflex Leica lenses...
they cover the format, and an adapter is easily made.
I tested with very pleasing results the Elmar 65/3,5 the tele Elmar 135/4 and Telyt 200/4
P1030513 by sergio lovisolo, on Flickr
tele Elmar 135 example
_IGP5124b by sergio lovisolo, on Flickr
Elmar 65 example
_IGP0376 by sergio lovisolo, on Flickr
Sergio
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Forum: Pentax Medium Format
03-06-2011, 10:59 AM
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Steven
in my case, only 120 macro and 300/4 required AF calibration.
The 120 was frontfocusing, and required a consistent -10. Now it focuses perfectly at all distances.
For the 300 only -3 was required, and is now spot on at all distances.
All other lenses, 35,75, 150 and 45-85 didn't require calibration.
Sergio
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Forum: Pentax Medium Format
02-25-2011, 10:09 AM
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Splendid images, all of them Steven. I imagine them printed 80x60 inches on the walls of an empty room with an armchair in the center.
Thanks for posting.
Sergio
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Forum: Pentax Medium Format
02-21-2011, 04:12 PM
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That is a smart trick,but is practical only if the number of exif to modify is limited. As an example, saturday's job was to document the area of a planned new highway 100 km long, and the number
of shots ended at more than 700. (don't know if a batch processing procedure is available for that pourpose)
I tried many geotagging softwares, (for Mac or windows), but direct connection of GPS to camera is
much preferable and practical.
A possible problem with the Pentax GPS module (from the images I have seen ) is that it must be connected to the hot shoe, while I need to position the antenna at least on the glareshield, for sky visibility. Hope that a cable or an external antenna will be available.
For Adrian: I have the eye-fi card. It is so slow that I will be back home before the transfer is finished.....but if you are not in a plane, a smart idea!
Sergio
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Forum: Pentax Medium Format
02-21-2011, 10:10 AM
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Cuchulainn, I use the method you suggest when the Nikon is unsuitable for the job, but it has a few downsides. Clock syncronization between camera and GPS must be very precise, as a few seconds difference means several hundred meters error (the aircraft speed is 40-50 meters per second) and this is not very easy to achieve, at least with the 645d that shows only minutes on the setting page.
Than there is the correlation work. Worst of all, you are not sure of the result before being again on the ground, and this creates a slight anxiety....
I prefer a direct connection between GPS and camera, with that little window (as on the Nikon) blinking when GPS position is unreliable.
Sergio
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Forum: Pentax Medium Format
02-21-2011, 09:04 AM
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Dave, hope to make some big prints soon, I am confident that quality will be very good.
Materialsguy, have you verified that the focus position does not change across the focal lenghts range
with the 55-100? I usually calibrate my prime focus lenses to infinity on the ground, and block them in that position with adhesive tape. This is not possible with Nikon zooms, as focus varies across the range, while the Pentax 45-85 seems to constantly maintain focus position with the various focal lenghts.
Thanks.
Sergio
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Forum: Pentax Medium Format
02-19-2011, 10:41 AM
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Today the visibility was good so it was time to do a pair of "job" shoots after one month on the ground.
The 645d performed as aspected, notwistanding the fact that I had to bring the D2X too, becouse one of them required GPS. I hope that the GPS upgrade will arrive soon for the Pentax.
The lens of choice was the 67 (late) 55mm F4 that I used at 5,6 iso 250 and with shutter speeds faster than 1/1000.
The 55 is a great lens, perfectly balanced and sharp from corner to corner. Moirč is present, but less invasive than with cameras with larger pixel to pixel spacing and no AA filter.
Full image first, than a pair of 100% crops.
_IGP0178r by sergio lovisolo, on Flickr
_IGP0178c by sergio lovisolo, on Flickr
_IGP0178cb by sergio lovisolo, on Flickr
For my work, this is the best camera I ever had, Linhof Aerotechnica included.
Sergio
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Forum: Pentax Medium Format
02-13-2011, 03:20 PM
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My experience with 645d is limited.
Usually I prefer iso 100 on tripod, with long exposures and time to correct errors.
This is the example I posted in the FA35 interior test, this copy corrected for white balance.
Seems that long exposures at iso 100 have very low noise.
_IGP0077 by sergio lovisolo, on Flickr
Sergio
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Forum: Pentax Medium Format
02-13-2011, 10:35 AM
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Steven,
according to DxO lab test, there is nothing to lose.
DxOMark - Pentax 645D
from their test you gain 1 stop in DR, but probably extremely accurate exposure is required to avoid
highlight blocking.
Sergio
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Forum: Pentax Medium Format
02-10-2011, 02:55 PM
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Forum: Pentax Medium Format
02-09-2011, 06:16 AM
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Forum: Pentax Medium Format
02-07-2011, 01:27 PM
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Alan,
I agree, most are very good, but 40 MP are really a challenge. I agree also that there could be some sample variation, as suggested for the 45-85. But I tested 3 of these, and all were showing the same defects : good center sharpness, but asymmetry on sides and corners, and acceptable usability stopped down at F11.
But escluding the zooms, that must be stopped down, and the 45 2,8, all the other are
outstanding or at least very good.
I'll prepare a list, with my findings, at the end of tests.
Thank you for your kind words.
Sergio
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Forum: Pentax Medium Format
02-07-2011, 01:07 PM
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Royce,
I don't have problems at any shutter speed. But my tripod is an old one I used with large format view
cameras with 3 axis articulating movements. Unfortunately weight is exactly 20 lbs....
P1030506 by sergio lovisolo, on Flickr
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Forum: Pentax Medium Format
02-05-2011, 10:51 PM
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My experience too. 67 55mm is a great lens on the 645. A great BIG lens...
Test shot at F8, full size jpg downloadable.
_IGP5016 by sergio lovisolo, on Flickr
Sergio
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Forum: Pentax Medium Format
02-05-2011, 10:25 AM
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Just a pair of shots and crops.I think this is another example on the lenghtening list of lenses with very good performance on the 645d.
The 300 required an AF correction of -3 to obtain perfect focus..
I have the camera from just a few days, and learning to use it, so not completely sure
of my results, but at the moment the only no no is the 645 FA45 2,8.
Full size jpg available on flickr.
_IGP5097 by sergio lovisolo, on Flickr
100% crop (note the spider web wire from the leave 1 pixel wide)
_IGP5097c by sergio lovisolo, on Flickr
_IGP5098 by sergio lovisolo, on Flickr
100% crop center
_IGP5098b by sergio lovisolo, on Flickr
100% crop near lower corner
_IGP5098c by sergio lovisolo, on Flickr
Sergio
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Forum: Pentax Medium Format
02-04-2011, 09:36 AM
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Forum: Pentax Medium Format
02-04-2011, 07:02 AM
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Thanks for kind comments.
This lens is really extraordinary.
A last one with a tridimensional situation at F11, with full size jpg compressed at level 10
in PS for upload limit in Flickr. Enlargement at 500% shows total definition in every point of the image.
Full size jpg also available on Flickr.
I apologize for the boring subject, just a view from my window.
Sergio.
_IMG5029 by sergio lovisolo, on Flickr
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Forum: Pentax Medium Format
02-03-2011, 02:11 PM
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There is a lot of discussion on this lens. I would like to propose a little test on my copy.
The first series of images (the most boring part) shows perforformance at center and corners on resolution targets. Pse note that chart distance is calibrated for 24x36mm format, so the readings must be divided by 1,27 to obtain absolute line pairs x mm on the 645d 44x33mm format.
Presence of aliasing (moirč) indicate that resolution limit of the sensor has been reached, with stronger aliasing as an indication of stronger contrast of finest details.
CENTER at F3,5
_IGP0083a by sergio lovisolo, on Flickr
CORNER F3,5
_IGP0083b by sergio lovisolo, on Flickr
The lens outresolves the sensor, albeit with less energy in the corner.
CENTER at F8
_IGP0085a by sergio lovisolo, on Flickr
CORNER at F8
_IGP0085b by sergio lovisolo, on Flickr
very good resolution, with strong contrast center and corner. Resolution maximum between F8 and F11
CENTER at F16
_IGP0087a by sergio lovisolo, on Flickr
CORNER at F16
_IGP0087b by sergio lovisolo, on Flickr
At F16 diffraction is prevailing, and resolution is reduced at the level of a 16MP camera.
From a resolution point of view, the FA 35 3,5 is outstanding from full open to F11, with a performance that can be hardly surpassed. In critical shots for moirč, it can be practically eliminated at F13.
INTERIOR EXAMPLE AT F13
_IGP0077 by sergio lovisolo, on Flickr
A full size jpg of this image can be downloaded from the "view all sizes" page on the Flikr link above.
EXTERIOR EXAMPLE AT F11 ( the usual brick wall)
_IGP0135 by sergio lovisolo, on Flickr
A full size is also available on Flickr
I apologize for the long post, and hope of not having abused of your patience.
Sergio
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Forum: Pentax Medium Format
01-30-2011, 12:25 PM
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infrared compensation for infrared filters
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Forum: Pentax Medium Format
01-30-2011, 10:05 AM
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Shuttershane,
there are no scales to calculate hyperfocal zone on the 45-85. A different scale is needed for every focal lenght, and it would be impossible or higly impractical from a mechanic point of view to print them on the barrel or provide a way to modify the scales for every focal.
Leica found a way to print scales for different focal lenghts on the tri elmar 28-35-50
Sergio
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Forum: Pentax Medium Format
01-27-2011, 04:10 AM
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Thanks for posting these shots, Steven. I was planning to buy a 67 45 tomorrow, and your tests are greatly appreciated. Could you post a pair of 100% crops?
Sergio
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