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Forum: Pentax SLR Lens Discussion
05-24-2022, 06:32 PM
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Macro lenses are fairly simple optically, I strongly doubt that a decent macro lens from even the 70s is going to be significantly worse than a modern one. Pentax, Nikon, Yashica, Lester A Dine, etc are all respectable lenses.
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Forum: Sold Items
05-09-2019, 09:25 PM
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Is this a standalone P6 to 645 adapter or has the lens been modified to 645 mount?
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Forum: Film SLRs and Compact Film Cameras
12-19-2016, 08:12 PM
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Possibly due to polarization changes as the lens changes angles relative to the sun? That's how I would explain that observation. Not sure that a handheld meter would be that much more accurate though.
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Forum: Film SLRs and Compact Film Cameras
12-19-2016, 08:03 PM
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This is largely what I was going to say last night but I decided to give it a rest and think it over. Here's what I wrote:
Well, it's got a known problem with sticky mirror syndrome, some electrical glitches that can manifest in a similar fashion, etc.
By all means, it's a very tightly sealed camera, but there are different kinds of durability too. Sometimes what you want isn't a fine watch with super-tight tolerances, sometimes a little "wiggle" room is what you need to keep it running in crappy conditions.
The US military famously demands much looser tolerances on its M1911 pistols than most target shooters will accept, to the extent that they are even considered "wobbly" in some cases - but in turn that keeps them firing though conditions that cause target 1911s to jam. So which is more "durable" - the pistol that is tightly sealed to keep crap out, or the pistol that accepts that crap happens and deals with it?
I would put out the Nikon F as probably the model of durability, as well as the Nikonos series. Your test here is the abuse of photojournalist usage, and those were the cameras they picked. Then the Nikon FM/FM2 and Pentax MX on a level below that, along with other similar all-mechanical cameras (K1000, KX, K2, etc).
By all means, the LX is a good camera... it's just one that you will probably want to have serviced on a regular basis, whereas you can just pick up a "beater" camera after it's sat for 30 years and it will "just work".
For the ultimate test of durability though... why not see how The Hydraulic Press Channel 'deels vit' some cameras? Think the LX will fare much better? :p (the surprise winner was definitely that Canon lens though!)
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Forum: Film SLRs and Compact Film Cameras
12-19-2016, 07:58 PM
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Yep - shutter isn't cocked until the wind lever is wound, shutter can't fire until the camera is wound, classic example of film binding and preventing you from winding... I was going to say the same thing last night but I saw you had sorted it!
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Forum: Pentax Medium Format
12-18-2016, 10:56 PM
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I say go with the 105/2.4 just because it's a little faster, but it's really up to you. Your normal lens isn't usually the go-to for landscapes anyway, so I don't think it makes a huge difference either way.
I would say to prefer the 90/2.8 or 105/2.4 just because they are optimized for near-infinity work. The 135mm Macro has some issues with near-infinity work, and the 100mm macro probably isn't its best near infinity either.
If you want to share filters, buy filters for your largest lens and step-up adapter rings for each smaller filter size. I use 77mm as standard, but this does mean that I can't use my filters on my 75mm f/4.5.
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Forum: Pentax Medium Format
12-18-2016, 10:07 PM
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I use a Kirk L-bracket, an Arca-Swiss B1 ballhead, and a set of heavy-duty carbon-fiber tripod legs (mine are Vanguard brand, but Induro or Gitzo or any other brand will be fine too). I recommend all of them highly. Nowadays you might look for the Arca Swiss Z1 as well, since it's replaced the B1 in their lineup.
You are going to have a bad time with the P67 on a light travel tripod. Possibly worse than handholding, in fact. The only weight-saving move I recommend is going with carbon-fiber rather than aluminum. The weight savings are real and do not compromise stiffness. I agree with desertscape here, your GT2542T sounds like a good place to start.
I didn't know Kirk discontinued the P67 L-bracket, I guess I made a good move buying a couple years ago, but darn, I was actually hoping to pick another up for my other body. I really don't think there is any substitute for an L-bracket, my advice is to hunt one down.
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Forum: Film SLRs and Compact Film Cameras
12-18-2016, 09:38 PM
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Yeah, Pentaxians tend to be 'thrifty' :p. $550 for a camera is expensive, there are better bargains out there for sure, but it's not Leica money. You can easily drop that on a nice Nikon F5 let alone an F6 or something. Or you can easily drop that on a decent telephoto lens.
And honestly just think about what it probably cost new in its heyday. These were not cheap cameras to begin with, that's why there aren't millions of them out there.
Nope, I've heard this too. They are not as durable as other SLRs, they are quite expensive to get serviced (and will only get more expensive as donor bodies become more and more scarce), and service is not going to be available forever.
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Forum: Film SLRs and Compact Film Cameras
12-18-2016, 09:28 PM
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If you are trying to do manual focus on an AF camera with a plain screen and no focus aids, you're going to have a very, very bad time.
If you want to go Pentax, you can't beat a ME or MX for manual focus, that big bright viewfinder is just wonderful.
If your darkroom has gear for medium format, why not a Pentax 6x7? That's pretty much my One True SLR personally. I had a split prism screen put in and it's perfect.
Also - if all you need is a 35mm, you can get an Olympus XA. Great lens, tiny camera. The Stylus Epics are really nice too, but no manual aperture control.
It sounds like you're really into the Canon P though, if that's what you want then why not just get that? :)
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Forum: Film SLRs and Compact Film Cameras
12-18-2016, 09:20 PM
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It's there to hold the paper flat. Just like a camera, the enlarger has a plane of focus and if the paper bows out of the plane of focus the image will be out of focus and soft.
You need some corner space for a place to stick the photo corners into, for the window mat to cover, etc anyway, so printing right to the corner is not a great idea anyway. If you don't like it, you can always just use a paper cutter to take a quarter inch off the edges once the print is finished.
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Forum: Film SLRs and Compact Film Cameras
12-18-2016, 09:06 PM
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Samyang works great on film cameras. I use my 35mm f/1.4 on my Pentax ME, it's a very, very nice viewfinder image.
The aperture is actually in the front part of the lens that does the tilting and shifting, not in the part that is fixed to the camera. In tilt/shift lenses it is very common for there to be no mechanical linkage from the aperture to the camera body because it would be very difficult to make that work properly. The distance between the mount and the aperture would change as you tilt and shift, so even a flexible cable would not work.
You need to go to an electronic aperture control like Canon EOS to get a tilt/shift lens that will stop down automatically. Otherwise you just stop it down by hand. It's just how T/S lenses work, and it's why they're not good general-purpose lenses.
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Forum: Pentax Medium Format
12-18-2016, 08:43 PM
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Yup, looks similar (but not identical) to the 35/2 AL.
Also looks similar-ish to the Zeiss Distagon 40mm f/4.
And here's the Distagon 50mm f/4 FLE CF:
Can't find a diagram of the Pentax 67 55/4 late lens, but since it's a Distagon type it may be similar to that. Or maybe not, some of the distagon versions were fairly different and those may be the ones the 55/4 is based on.
It's not real surprising that the 75/2.8 AL is so different, the 6x7 lineup was very straightforward in most ways. The lenses are mostly just standard designs (105/2.4 Planar type, 150/2.8 double-gauss type, etc) and largely consists of scaled-up designs from the 35mm lineup (which isn't to knock it in any way - it's actually a "greatest hits" collection of their vaunted K-series lineup). Apart from the zooms and the EDIF telephoto lineup everything is pretty conventional 70s-vintage lenses, so a modern aspheric lens is a departure from the rest of the line.
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Forum: Pentax Medium Format
12-16-2016, 04:29 PM
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This is always a problem on crop-sensor cameras (and the 645D and 645Z are crop sensors compared to 645 full frame). Unfortunately, the new lenses are very expensive indeed, but the older lenses weren't cheap in their day either. It's easy to forget that we are really getting a great bargain on all this professional gear that was horrendously expensive only a decade ago, but it's not cheap at all to produce sharp fast glass for a medium-format SLR.
Apart from the 35mm f/3.5 and the 33-55 zooms previously mentioned - the other thing you can do is adapt lenses, you should be able to get an adapter that fits most types of 6x6 lenses. I have heard some people rave about the Arsenal 30mm f/3.5. It's technically a fisheye lens but since you are using the very center of the frame the distortion is not too strong, and you can correct the remaining distortion in software. This costs you some resolution of course, but the 645D has a lot of resolution to spare, and it may get you the angles you want. If you adapt then you will lose auto-aperture function, but I think there may possibly be a native Pentax 645-mount version? Don't quote me on that, not positive.
Technically you could even do this with a scanned film negative/slide. The guy I know does it with his Pentacon Six. There's greater distortion and thus greater loss of field-of-view and resolution, of course, but it's just computer magic.
And of course - you can also do this with the Pentax 67 35mm fisheye as well! It's just not quite as wide, and remember that you do lose some angle/resolution doing the fisheye correction, so unless you have a good reason to want the P67 35mm Fisheye I would strongly recommend choosing the rectilinear P645 35mm instead.
With the -A lenses you can look at the lens barrel to see how far you need to turn to get to a particular distance. Goodguy K-Rock to the rescue, here's his shot of the lens. It looks like at least a 180 degree throw, possibly a bit more? Any manual-focus lens that's in good repair will have a nice smooth travel, and if it doesn't you should send it off to get cleaned because it probably needs it anyway.
As for the FA/HD variants - that question I don't know and don't have an easy way to tell without one on-hand, sorry. I can say that autofocus lenses typically have crap manual-focus handling, they tend to have very short focus throws (angle of rotation) because that makes the screwdrive work faster, and they often have no resistance (sometimes they're even "wobbly") because the focus motor doesn't like resistance.
The only auto-focus lenses that have good manual-focus feel are the focus-by-wire type. The problem there is you also introduce a little bit of lag between when you turn the ring and when the camera responds and focuses. So that's not really perfect either.
I imagine that it will probably feel like other FA lenses with the push/pull AF/MF selector though, so maybe someone else has one of those and could chime in? I really think the most you can expect is "loose and short throw, but smooth" though.
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Forum: Site Suggestions and Help
12-16-2016, 04:09 PM
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Awesome, thanks Adam! I know it's a pain to go through the reviews and split them out.
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Forum: Site Suggestions and Help
12-15-2016, 11:09 AM
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In the lens review database, many of the articles for older M42/K-series lenses show multiple different optical formulas for a lens at the top - sometimes significantly so. For example here's the Listing for Super/SMC Takumar 28/3.5:
The Super and SMC Takumar 35/2 are really different as well.
The Auto Takumar 85/1.8 and the SMC Takumar 85/1.8 share a page, and they don't even have the same number of elements!
In my opinion - if the lenses have non-trivial optical differences, they should have their own page in the database.
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Forum: Pentax Medium Format
08-29-2016, 12:56 PM
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Portra 400 is specifically designed for a hybrid-digital workflow. It's very low-contrast on film so it's easy to scan, then you push the contrast digitally.
Make sure when you scan that you pull the black and white points all the way to the edge of the exposed range on the film, and then adjust the grey point somewhere reasonable. Again, this will make your scan very flat, but importantly it contains all the information from the negative. You can boost contrast in post-processing.
One caveat is that if there is a blown-out region that's widely separated from a particularly important tonal region of your photo you may actually want to pull the grey point slightly towards the main region rather than towards what makes the scan look good right away. Each pixel only has a certain number of shades that can be displayed, and it's not good to crush that tonal space down. In extreme cases you may want to scan twice - once for the highlights, once for the main image - and digitally mask them together.
If you adjust the white/black points on color film do realize that you are actually adjusting three separate curves at the same time here (R,G,B). With some films the exposure shoulders are not in quite exactly the same place, so the highlights might go yellow (for example). You can adjust this by pulling the white point for just the blue curve in a little bit.
For your example, if "everything" (midtones) looks green, then adjust the grey point for the green channel.
You probably won't get it perfect at first but you can bring it a lot closer and get it right in Lightroom.
Also, consider getting a colorimeter at some point. Different types of screens have different coloration (TN tends to be greenish) and they change as they age and the backlights wear. Without calibration you have no idea what it actually will look like in print or on anyone else's screen. You can buy a color-calibrated IPS panel from Dell (P-series) and they will be pretty accurate, but they do drift as they age.
As for developing, nowadays I mostly use Rodinal - it's a "one-shot" so you don't need to worry about feeding your developer, and it lasts forever (unopened cans from 1920 are still good). Use it 1:100 stand developed for one hour for a universal "develops anything" formula - it looks very good with Acros. Many films can also be developed 1:50 for a shorter time. Consult the DigitalTruth online dev charts.
If you are getting B+W developed from a lab you will have very little control over your results, and probably poor quality to boot. It's very easy to develop B+W at home.
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Forum: Pentax Full Frame
06-21-2016, 01:52 PM
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Even Pentax is still using the Planar as a base. Every 50/1.4, 50/1.8, 50/2, 55/1.8, or 55/2 lens is a Planar at its heart. Pentax used to have some other designs back in the Asahiflex days - the 58/2.4 was a Heliar type and the 58mm f/2 was a Sonnar type.
The fact that coatings were finally coming of age was a major reason why the other types died out. They had fewer air-glass interfaces and so tended to flare less and lose less contrast. Once coatings fixed this problem with the Planar's many air-glass interfaces they faded away.
They seemed to work particularly poorly as SLR lenses, as there are some rather good Heliar and Sonnar lenses for rangefinders and LF cameras.
A lot of the modern lenses are essentially direct descendents of the film lenses, sometimes with few changes other than slapping a screwdrive on the focus mechanism. There would probably be some tweaks, but also probably less than you would expect.
Really that's been the story thoughout the process of lens development. What happens when you split the triplet's rear element into a doublet? Why, that's a Tessar. Replace the triplet's single front and rear elements with doublets? Well, that's a Heliar. Lens design has some specific rules and the modifications that can be made are pretty straightforward. There's a fantastic chart of the various lens families somewhere on MFLenses, but I can't seem to dig it up.
You can go hog wild and computer-optimize radical new lenses, but people don't seem to like that. If you want it, just buy Sigma.
---------- Post added 06-21-2016 at 05:04 PM ----------
My understanding/theorycrafting here is that speed tends to introduce abberations. The faster you go, the farther you are away from a theoretically-perfect pinhole aperture. Similarly, going farther away from a normal lens tends to be trickier too.
You have a certain number of element surfaces that you can use to focus the light. When you use your element surfaces to try and intensify the light or bend some insane field-of-view onto the film, you can't spend them correcting abberations as easily. So the slower lenses have less abberations to correct and more ability to correct them. Obviously, more elements gives you more ability to bend the light, but increases weight, cost, and complexity. And even with Super-Multi-Coating, at some point you will start to lose some contrast and flare-resistance.
In particular the SMCT 35/2 and K35/2 and it just never seemed worth it. It's not that great wide open compared to modern lenses and you're giving up the incredible contrast/resolution of the f/3.5 lenses.
The K28/2 is a Distagon, it's supposed to be a very nice lens, it's just way too expensive for what it is. The P67 55/4 is also a Distagon and doesn't cost an arm and a leg. The K30/2.8 is also much more affordable.
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Forum: Pentax Full Frame
06-21-2016, 12:51 PM
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This. The K-series was really Pentax's heyday, before they cheapened the designs and lightened the build quality.
It's about sharpness, not speed. The f/3.5 lenses are sharper wide open than most f/2 lenses stopped down. Unless you really need the extra stop and a half, they are a better choice.
As someone once put it, they don't think it be like it is, but it do.
Leica glow is spherical abberation. Smooth bokeh can be produced with defocus control or apodization elements. "3D effect" is the result of good microcontrast and good lighting.
I don't deny that certain lenses have something people define as "character", but it's definitely possible to optically analyze what's going on and replicate it in another lens. There is no "magic fairy dust element" in a lens.
It's fine to like the rendering characteristic of a lens, but don't over-romanticize it. It's perfectly possible to set an atmosphere with a new superlens, or even a crappy old lens. Historically most photographers have worked with something like a triplet, Tessar, or Planar, and that's that.
---------- Post added 06-21-2016 at 04:08 PM ----------
Yeah, the 50/1.2 is just scarce. It was an expensive lens and not that many were produced and sold compared to the 50/1.4s. It's not scarce in absolute numbers, but there's not enough to go around relative to the number of people who want it.
Forget modern lenses, personally I think 50/1.2s are actually the epitome of "bland, boring lens". It's the same Planar optical formula as a 50/1.4, except pushed so fast that the corners turn into mush. OK, whatever floats your boat, I'm not paying $600 for that. A 35/1.4 beats 50/1.2 any day of the week for low-light shooting, and there's tons of good-looking short-tele lenses for portraits.
I could see the merit of owning something like a 50mm f/0.95, but practically speaking I know the 35/1.4 is still just as good in the role and doesn't cost as much as a full P645Z setup.
The A* lenses are pretty overpriced in general. They're nice lenses, but they're very scarce and not worth the prices they go for. I'd rather shoot a K135/2.5 or a Nikkor 105/2.5 and keep the money in my pocket.
I would actually put the K28/2 in the same boat. I'd love to own one, but I can't justify it. The K28/3.5 is fantastic too, and much more reasonably priced. Oddly, the K28/2 and K35/3.5 are dirt cheap in their P67 incarnation - you may know it as the Pentax 67 55/4 and the P67 75/4.5. :D
---------- Post added 06-21-2016 at 04:18 PM ----------
This is absolutely pathetic, guy's blaming the lens for differences in lighting and small variations in focus placement.
The comparison with "flat nose and head" is different because the background in the second is farther behind and thus is more out-of-focus, meaning the subject is more isolated. And sure, defocus-control lenses isolate the subject from the background very sharply - but wasn't he just complaining about modern characterless super-lenses?
The one thing I will say is that I think aspheric elements can sometimes give funky bokeh. Not nervous, not ringed, just "weird" somehow. Might be something to do with apodization caused by light passing differently through the aspheric elements or something. Could just be a lack of spherical abberation, or all in my head.
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Forum: Pentax Full Frame
06-21-2016, 12:21 PM
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Tiny P+S sensors like the FZ1000 and Q are the least likely to outresolve a lens. The Pentax-Q is diffraction-limited from f/4.
---------- Post added 06-21-2016 at 03:33 PM ----------
Pentax was way head of the curve on coating and any prime with SMC basically "just works". I've only had a handful of lenses which were flare-prone (M28/2.8) and I blame the optical design more than anything. Vintage zooms are a lot more hit-and-miss across the board, typically I think you're better giving them a pass unless they're something like a 70-200.
The major difference between legacy and modern lenses is actually telecentricity. Film picks up light at any angle, but digital sensors capture it best when it's coming straight inwards. Modern lenses are designed to put their optical center at infinity, so the beams of light are always coming straight in, but this wasn't a design consideration back in the film days. This means that some designs are great on film and just plain bad on digital. It's a fairly common problem in wide-angle lenses.
And yeah, certainly there wasn't as much focus on edge sharpness. Particularly wide-open edge sharpness - in most lenses it's there to help you focus more than anything, although there are of course exceptions. "Superlenses" in general - 24mm and wider lenses, supertele lenses, superfast lenses, etc - just tended to be poorer due to worse design, worse manufacture, fewer types of exotic glass available etc. You owned a 20mm lens, who cares about the corner sharpness?
If you guys really want a sharp lens at a good price, pick up a Samyang 35/1.4, 24/1.4, or 135/2. The 50/1.4 and 85/1.4 are not that impressive though.
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Forum: Pentax Full Frame
04-12-2016, 07:05 PM
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Too rich for my blood but I love my Samyang 35/1.4. A 35/1.4 is really a must-have IMO, it's a fast-normal on APS-C and a fast-wide on FF. A very necessary FL on both formats.
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Forum: Pentax Full Frame
04-12-2016, 03:55 PM
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Actually it's because live-view is usually contrast-detect. CDAF is actually more accurate than phase-detect autofocus and doesn't suffer from situations where there's not a sensor at the focus point selected - the downside is that it's much slower than PDAF. There are some sensors with special phase-detect pixels that can focus a MILC-type body pretty much as fast as SLRs. In theory you could use PDAF for the course focus and fine-tune it with CDAF, but you'd risk missing focus on a rapidly moving target.
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Forum: Pentax Full Frame
04-12-2016, 09:09 AM
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Yes, most of the Samyang lenses are quite fantastic and many allow you to replace many of the rare/expensive star-series lenses. 135mm f/2, 35mm f/1.4, and 24mm f/1.4 lenses fill some important but expensive niches in many kits. There are a few duds however - the 85mm f/1.4 and 50mm f/1.2 don't produce the same image quality as the rest of their line. And obviously you have to be willing to deal with manual focus. A split-prism focus screen will make this much easier.
Anything in the Sigma Art series is also fantastic, they're on the pricier side but you get what you pay for. The DG Art 50/1.4 is a major step forward from the basic Planar 50 design that dominates the first-party lineups, and the 35/1.4 also outperforms the first-party lineups.
The K35/3.5 is also a real gem on film, and the K28/2 reportedly is as well. YMMV on old lenses, some sensors tend to be sensitive to the tele-centricity of the lens and don't perform as well as they do on film. In general it's safer to opt for newer lenses that are optimized for this characteristic.
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Forum: Pentax Full Frame
04-12-2016, 08:51 AM
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It all depends on what kind of shooting you do. If you usually shoot in good light or with flash, it's not a problem. Image stabilization gets you even farther nowadays.
But if you're going to do available light photography in areas where light is not available, high ISO is quite useful. Typically the very highest ISO setting on any given camera is useless for artistic imaging, but it's nice to know it's there. Down one stop is quite noisy and some loss of sharpness, but usable if needed. Two stops down is usually quite good. On my NEX-5N I find that ISO 6,400 to 12,800 and a Samyang 35/1.4 let me shoot in some quite dark areas without a flash, and I find this useful. A stabilized sensor would be even better for many subjects.
Obviously at that point you do get some noise. Typically applying chroma noise reduction will mostly fix the problem - it's still there but much less noticeable. Lumi noise reduction will reduce the leftover grain, but it also hurts sharpness. Typically though some grain doesn't look out-of-place for the shots where you are using those kind of settings though.
At this point it's pretty much a "gimme" in any sensor that's new within the last 5 years. There's nothing wrong with keeping that capability in your back pocket in case you need it.
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Forum: Sold Items
01-14-2016, 11:21 PM
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The Takumar and K series were a pattern of increasing complexity - from a 7-6 design to a 7-7 design to finally an 8-7 design.
The M series was a drastic cutback in complexity across the board. The M 28/3.5 was a much simpler 6-6 design. Overall it's not as good as the K series or even the Takumars, but it's still simpler to design slower lenses and it's still a better overall performer than the M 28/2.8, which was a touch soft wide open and had a big flare problem.
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Forum: Pentax Medium Format
11-09-2015, 09:20 PM
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FWIW I'm viewing at 4K and she's still sharp.
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