Forum: Pentax SLR Lens Discussion
12-07-2023, 10:10 AM
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I love the Pentax F 17-28mm on the K1ii. The lens even works on my Fuji GFX medium format camera. From 17 to 21mm, there is some mechanical vignetting due to the lenshood petals but from 22mm to 28mm it covers the whole sensor.
Cheers!
Abbazz
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Forum: Lens Clubs
08-03-2023, 03:29 AM
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There might be a confusion between plain old WD-40 penetrating oil, which is a lubricant spray used to loosen rusty bolts and stop hinges from squeaking, and WD-40 Contact Cleaner, which is a solvent spray designed to remove dirt, oil and grease.
Here's the plain WD-40 (don't use it on your adapter, it will leave an oily residue):
And here is the stuff you need to clean your adapter (it cleans the electrical circuits and leaves no residue):
Cheers!
Abbazz
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Forum: Pentax Medium Format
08-02-2023, 02:15 AM
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Try to press the filter against a soft rubber sole laid on a flat surface, while unscrewing the lens with both hands.
Cheers!
Abbazz
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Forum: Pentax SLR Lens Discussion
07-24-2023, 09:24 PM
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The plain old Pentax FA 35mm f/2.0 is a great lens on Fuji medium format mirrorless cameras. The extreme corners are a bit soft (we are talking about a few pixels here) but vignetting is invisible at F/5.6-8 and image quality is great. Worth a try!
Cheers!
Abbazz
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Forum: Pentax Q
07-20-2023, 09:15 PM
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Forum: Lens Clubs
07-08-2023, 04:18 AM
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You're welcome!
Cheers!
Abbazz
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Forum: Lens Clubs
07-06-2023, 12:28 AM
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A few pictures taken with the Cinelux-Ultra 135mm f/2.0 on my Pentax 645D. Two stacked 65mm helicoids were used to get closer focus.
Cheers!
Abbazz
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Forum: Lens Clubs
05-31-2023, 03:34 AM
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You are indeed right about these macro lenses. But 58mm is the shortest focal length for an SLR Heliar type lens. It wouldn't be physically possible to build an SLR Heliar type lens with a shorter focal length because it would need to sit closer to the image plane than allowed by the mirror box.
Other lenses available in SLR mount are all in the telephoto range (even though the angle of view of a 135mm lens on 6x7 film is not much narrower than a 58mm lens on 24x36mm).
You can sometimes find the 58mm f/2.4 Takumar for cheap by looking for old non-functionning Asahiflex or Tower 22 / 23 / 24 cameras (the 58mm f/2.4 was sold as a kit lens for the Asahiflex). But then you will have to find an adapter ring from M37 to M42...
Cheers!
Abbazz
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Forum: Lens Clubs
05-23-2023, 01:34 AM
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The Takumar 58mm f/2.4 is in fact a very special lens. It is the only normal lens designed for a 35mm SLR camera featuring a Heliar/Dynar optical formula.
The Heliar is a 5 element / 3 group lens designed at the beginning of the 20th century by Dr. Hans Harting and made by Voigländer. The Heliar lens rapidly became a favorite of portraitists because of its rendering qualities, and especially its smooth depicting of out of focus backgrounds (which was not called bokeh at the time but already mattered to some photographers).
Heliar lenses are rarely made nowadays because they are relatively expensive to manufacture and their small number of elements does not allow the design of fast lenses with good correction of aberrations. In recent times, Cosina-Voigtländer released three different Heliar lenses (a 50mm f/3.5, a 50mm f/2.0 and a 40mm f/2.8) but they were all designed to be used on rangefinder or mirrorless cameras.
Pentax used the Heliar formula to manufacture the Takumar 58mm f/2.4 and this lens is indeed a superb lens for portrait photography. Try shooting at close range with this lens set to f/4.0 and you will see what I mean...
As for the Asahiflex cameras, they are indeed very nice. Build quality reminds me of Barnack Leicas and their size is also comparable. Even the shutter sounds like old Leicas.
Like you, I have an Asahiflex IIb. It has been delivering superb results with great reliability for a few decades already...
Cheers!
Abbazz
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Forum: Pentax Medium Format
05-04-2023, 07:28 PM
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Forum: Pentax Medium Format
05-04-2023, 03:20 AM
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What makes you think 220 film is not available? You Tube |
src="https://www.youtube.com/embed/46mrdP-re38?controls=1" allowfullscreen> |
Cheers!
Abbazz
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Forum: Pentax SLR Lens Discussion
03-24-2023, 05:55 AM
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No aperture ring is acceptable for a kit lens but not for an expensive Limited lens. Even worse, due to the KA4 mount with electronic aperture control, the lens cannot be used on my Sony a7rii or any other camera except a few recent Pentax models.
On my Pentax K1ii, autofocus is very unreliable with this lens, with lots of misfocuses. And I am not the only one to complain...
Last but not least, there is no infinity hard stop, rendering the lens unnecessarily difficult to focus to infinity for nightshots.
Considering the price, this is a no buy. Oh, the OP already bought it? Hopefully, it's not too late to apply for a refund!
Cheers!
Abbazz
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Forum: Pentax K-1 & K-1 II
03-07-2023, 05:41 PM
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There is no difference in image quality if you shoot only at low ISO. So my adavice is: just buy the newest camera with the lowest shutter count you can find for a good price.
Cheers!
Abbazz
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Forum: Pentax SLR Lens Discussion
02-27-2023, 10:06 PM
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Voigtländer lenses in PKA Mount, and especially these two, are my favorite too. The 40mm f/2.0 and the 90mm f/3.5 are dynamite in a small package: really good image quality, close focusing ability and great build quality. Add a 20mm lens and you have a small kit capable of handling almost any photographic opportunity.
I also have other great Voigtländer lenses in PKA Mount (20mm f/3.5, 58mm f/1.4, 125mm f/2.5 and 180mm f/4.0) but I don't use them as often as the 40 and 90 duo. These two really never leave the small bag with the K1-ii.
Cheers!
Abbazz
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Forum: Pentax Medium Format
02-26-2023, 09:57 PM
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Your TTL Prism is the version 2.0 with a GaAsP meter cell (the first version had a CdS element). The very detailed "étude" (study) published in 1983 by the French magazine Phot Argus had a lot of technical details regarding the Pentax 6x7. It is available online here: https://galerie-photo.com/manuels/pentax-etude.pdf
It's obviously in French but there are a lot of useful illustrations (including a superb exploded view of the camera) and it should be possible to use Google Lens to translate the useful bits into almost any language.
The TTL metering circuit described on page 4 is the same as yours with three potentiometers:
The text beneath says: "The circuit board features two inegrated circuits (one for measuring purposes, the other one being an operational amplifier for processing the current delivered by the sensor), three adjustment potentiometers (to be used only for maintenance by an approved service center) and a few discrete components."
So my advice is that I wouldn't try to tamper with these potentiometers.
Cheers!
Abbazz
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Forum: Lens Clubs
02-12-2023, 11:25 PM
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Nice picture. As usual, I prefer the fisheye perspective rather than the perpective from an ultrawide rectilinear lens (or a defished image like here). If you pay attention to he painting in the center part of the ceiling or the lady next to the bottom left corner, they both look much more like in real life in the fisheye picture. In the defished picture, they look elongated and distorted.
Cheers!
Abbazz
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Forum: Pentax SLR Lens Discussion
02-09-2023, 02:11 AM
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The Katoptaron 500mm f/8.0 is a high quality lens built on this design. It is unique because it offers certain advantages of a reflex lens (no chromatic aberrations and 100% UV transmission due to no glass element in the optical path), while retaining some of the advantages of a conventional refractive lens (no "donut" bokeh, viariable aperture adjustable from f/8 to f/32 via an iris diaphragm).
Here are some details about the Katoptaron lenses: https://www.pacificrimcamera.com/rl/00914/00914.pdf UV Buttercup with Katoptaron LDM-1/s
Cheers!
Abbazz
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Forum: Lens Clubs
02-01-2023, 12:15 AM
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You're missing the 70mm:
The 18mm "Pan-Focus":
The 20-40mm zoom:
And the 1.7x teleconverter:
Cheers!
Abbazz
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Forum: Pentax Medium Format
01-17-2023, 02:58 AM
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I would say it depends on your project. If it's only an image quality thing, then you will be better served with a last generation 24x36 digital camera than a Pentax 645D or Z.
I bought my 645D in order to be able to use my Pentax 67 lenses on a digital camera, especially the 105mm f/2.4, which I love. I think the image circle of the Pentax 67 105mm gets cropped too much on a 24x36 sensor. Its special rendering starts to appear on a 33x44 sensor and it really shines on 6x7 film. If I had more money, I would buy a camera with a 40x53.4 sensor but, in the meantime, the 645D is the best digital camera I can afford to use my 105mm lens. So, for my needs, the 645Z would not provide any sensible advantage over the 645D.
When I want to shoot at 12,800ISO, get the best dynamic range or use live view, I take my Sony A7Rii, which also happens to be much more light and compact than the big 645D.
Cheers!
Abbazz
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Forum: Pentax K-1 & K-1 II
01-02-2023, 03:09 AM
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For fun lenses on my K1ii, I would pick either the F 17-28mm Fish-eye or the FA 28mm Soft. These are unique to Pentax are are a lot of fun to use. The 28mm Soft is not very common but it's an exciting lens that focuses very close and produces the smoothest bokeh you can dream of (click on the picture to see it full size):
Cheers!
Abbazz
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Forum: Vintage Cameras and Equipment
12-23-2022, 06:34 PM
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I would favor the period M series lenses on the Pentax MX. A small kit comprising the M 20mm f/4, the M 40mm f/2.8 and the M 85mm f/2 would handle almost any shooting situation wirh superb results while fitting in a small fanny pack.
Cheers!
Abbazz
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Forum: Pentax Q
12-23-2022, 05:16 AM
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When I look at the EXIF, it appears the focal length was set at 77mm. That's why the image stabilization seems inefficient. If the focal length is not set correctly –and especially if the set value is more than the real focal length of the lens– then the Shake Reduction circuit will not compensate for the right amount when it detects sensor movement.
When using an adapted 25mm lens, the focal length should be set as such when prompted during camera startup, and not as a so-called "equivalent focal length" based on the sensor "crop factor."
Cheers!
Abbazz
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Forum: Pentax SLR Lens Discussion
12-05-2022, 08:50 PM
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Why the aggessivity?
On the DFA21, when I turn the focus ring to the right until it stops and take a picture at infinity, the resulting image is not sharp at all at any aperture.
The hard stop on this lens is way past infinity.
Thank you for explaining how to use an ultra-wide lens (although 21mm is more in the "super-wide" category in my book).
When I look at the distance scale on the DFA21, it doesn't seem well suited to manual focusing:
At f/2.4 on the Pentax K1, the hyperfocal distance is 6.2m. How is it possible to manually focus the lens to 6.2m, considering there is aboslutely no markings between 1m and infinity on the distance scale?
Cheers!
Abbazz
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Forum: Pentax SLR Lens Discussion
12-04-2022, 09:27 PM
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I have both lenses and the DFA 21 mm is the better lens from an optical quality point of view.
The zoom is quite good for what it is but it exhibits more field curvature at 21mm than the prime lens. It is also obviously much more bulky but it is more versatile and can be used on older cameras or adapted to other brands.
On the other hand, I see the DFA 21mm as a somewhat crippled lens: this is the first limited prime with the new KAF4 mount, which means it's only possible to use the lens on a few recent Pentax cameras (I cannot use it on my Pentax film cameras or on Sony digital cameras, even with an adaptor allowing focus control); it's also very difficult to use in manual focus because the focus throw is short and there is no infinity stop, which is particularly unfortunate because ithe autofocus often misses on my K1-ii.
Cheers!
Abbazz
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Forum: Pentax SLR Lens Discussion
11-27-2022, 10:23 PM
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The Sigma 24mm f/1.8 EX DG is a good lens, although quite bulky. At f/1.8, the image is not very sharp outside of the center zone but the fast aperture is great for blurring the background in close-up pictures. For landscape work, the aperture should be closed down to f/8.
Cheers!
Abbazz
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