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Forum: Do-It-Yourself
06-22-2014, 07:42 PM
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All,
I've put together what I hope is a most helpful annotated guide to servicing the Super-Multi-Coated TAKUMAR 1:1.9/85. I left a few things out that I wanted to include (this is the first instructional guide I've made) but in any case I hope that you will find it to be first-class. I welcome any feedback you may have since this is my first major post to PF.
JB Media | S-M-C Takumar 1.9 85mm Refurbish
I've 100% rebuilt quite a number now: most models in the Takumar series from 20mm-300mm, and a few from the K and M series. I'm meticulous. Typical rebuilds with no complications take me about 3-4 hours to complete. Longer for the more complicated lenses.
Mods, can someone please add this to the Pentax Lens Disassembly Database? thanks.
I'm all ears if you have any questions, or if you have suggestions on which guide to make next.
Regards,
jbondo
---------- Post added 06-22-14 at 09:53 PM ----------
Newbie mistake, Looks like I should have posted this to "Maintenance and Repair Articles". Can a mod move it there?
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Forum: Pentax K-1 & K-1 II
03-03-2017, 09:33 AM
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S-Type screens are a different case, and their value is not in the etchings/markings, but rather in the fact that they accurately show DOF below ~F2.8.
(Virtually all other screens do not because they are optimized for higher brightness at smaller F stops. They accomplish this at the cost of being to accurately display DOF <~ F2.8.)
I have no interest in etchings or prisms. I only want an S-type for manually focusing very fast lenses. :)
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Forum: Pentax K-1 & K-1 II
10-28-2018, 05:40 AM
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I know that everyone has their own unique approach to thinking about how to shoot and I respect that! That's what makes us all individuals.
My particular way of doing things is to break things down in to steps and consider each step in the order they occur. It's not 'right' or 'wrong' per se. It does bring a great deal of clarity to my thinking about what I am doing and helps me make more effective decisions about adjustments.
There are two scenarios here:
1. C-PL is in front of lens
If we expand upon UncleVanya's previous post:
We get:
Sensor | Color Filter Array (CFA) | Lens | C-PL | Light < --------
in this case It's all about what I want to do with the light before it enters my lens - and therefore my use of a C-Pl has no relationship with which lens I am using. I'm already done with thinking about what I want to do with the polarization aspects of the light before I ever start thinking about what I want to do with the lens. The reason for this is because this is the order in which these things occur. I keep them separate.
2. C-PL is behind one or more surfaces with HD coatings (drop-in filter)
Sensor | Color Filter Array (CFA) | C-PL | Lens | Light < --------
In this case the subcomponent of the light that is scattered internally as it passes through the lens may not have the same polarization state. Therefore the C-PL may have reduced modifying capability.
Even though my working style is essentially the same in both scenarios, my mental model is quite different. I think about what the C-PL is doing when it does it.
Now, with all of the above being said, there is a reverse case to consider:
Q: Is there a case when the lack of HD coatings contradict the use of a C-PL?
A: Yes. In extreme contrast situations (high illuminance) especially if both the lens and the C-PL do not have excellent coatings, you can get a lot of internal reflection between the front element and the filter so you're better off not using the filter.
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Forum: Pentax K-1 & K-1 II
10-23-2018, 06:35 PM
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Northrup often has pretty good advice. That particular video was disappointing. Yes, there are numerous times when no filter is superior to using one. The cases he made though didn't illustrate the uses of filters when they are most effective. It's as if the all the cases he made were to specifically sell that you shouldn't usually use one. (imagine that...)
A little knowledge about the physics of polarization can go a long way towards getting the best use of one.
- There is no direct substitute in post processing because our consumer cameras don't record raw polarization data, only illuminance.
- The strongest sky darkening always occurs when your shooting axis is at 90 degrees from the sun. (or whatever the illumination is if it's at night.) Shooting near 0 or 180 from the sun especially is often unproductive.. but not always because sometimes bounced light needs to be modified.
- Unless you're intentionally creating an uneven effect, don't exceed 45 or so degree angle of view as you will be unable uniformly apply to all areas in frame.
- Particulate haze and smoke can respond to polarizers in some circumstances, but it depends on the size of the particulates.
- Glare reduction and sky darkening are not the only uses of a polarizer. Tony fails to mention that a polarizer can also positively accentuate reflections and illumination when desired for creative use. - Including eyes.
- Some materials (pearlescents, fine grained sparkles) can respond superbly to polarizers because the nature of the shimmer is from reflecting light from many angles. You can shape the nature of the glimmer.
- I've used DXO Clearview a quite lot, It can be useful, but lacks the nuance possible with a polarizer. I have sometimes use both in the same image because they accomplish things differently.
- Utterly indispensable when you want to blacken a lit LCD screen near your subject. Has saved me from extensive post editing on several corporate gigs, not to mention easier metering.
- Nothing makes a rainbow pop like a polarizer because the internal reflections within the raindrops are different polarization than the surface reflections (but wide angle of view may be a limiting factor.)
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Forum: Pentax SLR Lens Discussion
10-09-2018, 04:22 PM
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Fellow Musician (I play in two bands) here.
At smaller / mid sized club venues, and for 3+ member bands
The 35 will have a lot more utility than the 50.
They both have similar light gathering power (even though the 35 is slower, it has a much wider angle of view)
the 35 will be a little more forgiving with focus / DOF
For larger venues (or where you cannot be close to shoot) or smaller 1-2 member bands:
The 50 may be a little better.
Also the 50 can also be better if your subjects are really still and don't move much, you can go for shallow DOF.
Here's a sample vid with 7 camera angles of which 3 are Pentax: K-1(31/1.8) K-1(DAF50/1.4) K-01(8/4 fisheye (de-fished))
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Forum: Post Your Photos!
09-29-2018, 10:26 AM
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Corvid fan here. Definitely a crow. Looking forward to more pics!
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Forum: General Photography
09-22-2018, 12:33 PM
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I frequently use Pentax lenses on other bodies.
I sometimes use non-Pentax lenses on Pentax bodies.
We're not all 'fan boys' whom insist upon a single brand. We're a pretty accommodating bunch. :)
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Forum: Pentax SLR Lens Discussion
07-03-2017, 12:44 PM
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I own both the Pentax A* 135/1.8 as well as the Samyang 135mm F2. While I have yet to have time to do a strict head-to-head comparison, there one attribute that is important to me that I have never seen mentioned in any discussion or any review anywhere. That is the transmittance. The Pentax has much more transmittance at F2 than the Sanyang at F2 And at F1.8, due to the greater transmittance, the Pentax is far better in very low light situations. Much more so that it would be apparent if you were only looking at the specifications. The Samyang has a little better bokeh for branch-y objects at very far distances. The Pentax has outstanding bokeh at near to medium distances. It may be a month or two before I can do a shootout. I'll post one as soon as I can.
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Forum: Photographic Technique
09-13-2018, 11:01 AM
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I share this same sentiment.
I a semi-pro musician as well as photographer videographer. I have a 50 fixture lighting rig and program the light shows my bands use.
Trying to achieve 'perfect' white balance often diminishes the impact of the lighting. Stage lighting is generally not about a 'natural look' but about being visually interesting/entertaining.
Video is a different matter, because you don't have the latitude that shooting in raw offers. Depending on the venue and the nature of the lighting (if the changes are not too fast, etc.) I will sometimes shoot auto white balance, but more often I'll shoot fixed between 4200K and 4800K.
Sometimes you can't help some of the lighting situation - like this recent gig where the house overhead washes were random colors and not coordinated with the band's light show. Auto WB can do some really odd and bad things in that kind of light. If you're shooting multiple cameras it's MUCH easier to color match the angles if all the cameras are set to matching fixed kelvin.
For stills of backlight subjects,extreme colors often work well.
For stills close-ups, especially of faces, I try to time my snaps where there is frontlighting is white (or at least not monochromatic) and the backlighting is strongly colored.
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Forum: Pentax K-1 & K-1 II
09-12-2018, 03:25 PM
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Bear in mind that high quality audio results can also be achieved by recording the audio separately without wireless, and and then substitute in that audio in during post production. A small dedicated recorder in a pocket with a wired lav can produce excellent results at a much lower cost than a wireless rig. The audio circuitry in the K-1 is good but not spectacular, so recording separately may actually produce better results.
I recently shot this video for my band.
Used two K-1's one K-01, a 6D + couple of go-pros and even some cell phone footage.
An older copy of Sony Movie Studio (12-14) is quite cheap and powerful. the suite comes with a DVD burning package.
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Forum: Pentax DSLR Discussion
08-21-2018, 04:07 PM
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645z body
A1200/8
HD DA560/5.6
- ALL OF THEM!
...ok, ok, I'd flip a coin to pick one.
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Forum: Troubleshooting and Beginner Help
08-20-2018, 12:05 PM
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That's a bummer. Just this June at Texas Motor Speedway, I took the rather large and hefty SMC Pentax-M* 67 400mm F4 ED [IF] to the Indy race, and the gate staff didn't object, in fact they said 'that's awesome!'
I hope the changes at Bristol don't mean the policy is changing everywhere.
One trick I've used to get some medium big lenses into venues that wouldn't normally allow them is to carry the camera with a small lens, and then to separately carry a bigger lens with a Monocular Converter K attached. The staff just thinks it's a visual instrument at the gate..then later I pop the big lens on the camera.
The Samyang 135mm f2.0 ED UMC with a teleconverter like the AFA 1.7 in the pocket would probably be passable.
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Forum: Pentax K-1 & K-1 II
08-19-2018, 03:10 AM
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Great shot. What was the ambient temperature? I've shot 1500 and 3500 nearly continuous on several different occasions, and shot video continuous for 4 hours and not experienced any issues. (The ambient temp was never over 95F, though.)
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Forum: General Photography
08-14-2018, 04:06 PM
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This is my experience as well. Tests done at F16 as others have recommended are only valid at F16. That test is not reliable for wider apertures.
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Forum: Pentax Price Watch
08-06-2018, 03:27 PM
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Like HarisF1, I have both.
Sharpness: Samyang is sharper wide open. Pentax has some CA from f1.8-2.2, and it catches up to the same league about F2.4. From 3.2 up, both are super sharp and well corrected.
Color Rendering: Pentax is better. I don't like the blues of the Samyang. It's a pretty big difference for portraits.
Bokeh: Under some circumstances Pentax bokeh balls make colored outlines. Despite this, the Pentax bokeh is more pleasing.
Transmittance (T-stop): The Pentax passes significantly more light at F2 than the Samyang does at F2. Wide open it handily beats the Samyang in t-stop, making it superior for (non-astro) low light shooting.
Astroprotography: Near wide open, the Samyang has superior color correction from about 420nm on up to the near UV, making it superior for star photos.
Build/feel/usage: Pentax is much heavier. Pentax quality/feel wins by a mile. Also, you may have to try more than one copy of the Samyang to get one that's uniformly sharp in each corner. (my first one wasn't)
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Forum: Pentax Price Watch
07-23-2018, 05:10 AM
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it has been serviced, but doesn't state the specifics of what it was serviced for - 'We performed disassembly cleaning, focus adjustment, zoom function adjustment at a specialty shop' Given the external physical appearance, I'm wary of possible element etching if the reason it was serviced might have been due to fungus.
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Forum: Pentax Price Watch
03-15-2018, 12:13 PM
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First time ever I've seen eBay offer that kind of rebate. Just received the FA77 I scored $100 off that was already at a great price before the rebate. Just fantastic.
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Forum: Giveaway Archives
03-04-2018, 06:57 PM
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Thanks for the list. I was aware of these, but It's been a while since I checked out Andrea K's effort, I'll grab the latest copy and see how it's progressed.
---I don't want to go too far off-topic on this thread, so I'll stop replying here and put future posts into the threads that they belong in. Thanks again!
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Forum: Pentax Lens Articles
06-13-2017, 02:25 PM
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I just realized I forgot to post this here.
It's the very carefully controlled and processed series of before and after vignette shots of the DA* 60-250mm F4 ED [IF] SDM rear baffle mod. Hopefully it's the definitive series for anyone with questions.
Also... not shown is that I also did another series with no rear baffle at all. Those results were indistinguishable from the modded configuration so I didn't include them.
As far as sharpness and aberration control goes, it does deteriorate a little (especially CA) at the edges, but overall, perfectly usable.
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Forum: Pentax SLR Lens Discussion
07-03-2017, 01:42 PM
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I wonder if this is a case of the camera needing to be more sufficiently stabilized for the focal length and shutter speed used. Or perhaps of SR needing to be turned off when tripod mounted.
I've shot close to 100K images on a 6D using 100+ Pentax lenses. I shot about 55K images on my pair of K-1's, which I of course use much of the same glass on. I also do astrophotography and routinely push resolution to the limit. I have yet produce any photo results where my 6D outperformed the K-1. (The 6D does has better video at top resolution in ALL-i mode in good light.) Now I will say that when the K-1 first came out, I falsely thought that it was not as sharp as it really was when I zoomed in all the way using live view. It was only when I realized that the K-1 has a much higher zoom ratio in live view that I realized it was a misconception on my part. With the same glass the K-1s outperforms the 6D in nearly all respects. The 6D is only better at lower weight, some video modes ...and autofocus when using native lenses.
Sharpness is not always the more important quality to me, but since you are asking, the sharpest lens I have is an exceptional A50 2.8 Macro. (but it does not have as good of contrast as the modern equivalents.) I suspect that factors other than the bodies are causing the differences you are seeing.
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Forum: Pentax Lens Articles
06-19-2017, 03:40 PM
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All tests were done to produce the maximum vignette, which happened to be infinity focus at 250mm. So the photos you see are the absolute worst case you will encounter. It was actually much better at shorter focal lengths and at closer focus. Sorry, I didn't take any "best case" photos. The reasoning being that I didn't want to get anyone over optimistic about what to expect. I figured worst case was the way to go.
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Forum: Pentax K-1 & K-1 II
03-01-2017, 05:01 PM
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I would love an S-type as well. Wondering if switching out will cause metering issues, though. On my Canons, you must tell the camera which screen is installed when you switch or they don't meter properly.
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Forum: Pentax SLR Lens Discussion
01-30-2017, 03:35 PM
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Only had time to snap a couple of bird pics in the back yard, and a few around the house, but on first inspection, I am not seeing any increase in abberations, nor any notable bad behavior. My guess is that the baffle just reflects that the FF designed lens was optimized for aps-c since Pentax had no FF at the time it came to market. Next time I have a chance, I'll do some astro-photos with it, which are an 'acid test' of any lens. I'll post the results next time I have an outing with it.
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Forum: Pentax SLR Lens Discussion
01-29-2017, 07:03 PM
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Thanks for your patience. Been busy with work and the bands. Re-aligning the barrel ended up being trivial compared to cutting it. Used an old film body to confirm exact alignment. (Now I can key the fixture.)
Here are the before and after shots under very carefully controlled conditions.
60-250 mod - Vignette before and after shots. |
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Forum: Pentax SLR Lens Discussion
01-08-2017, 09:25 PM
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OK, made prototype jig to do more of these and did the initial mod on mine. I'll have to wait for daylight clear skies to see if got the geometry right or if it will need refinement.
(I purposefully did it without separating the SDM contact ring from the tube. - if I got it right, I'll use the SDM contact ring to create a key on the jig, so all future ones will be identical.)
Edit: I removed photo with incorrect alignment so as not to confuse anyone. See my later post with the correct alignment.
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