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Forum: Pentax News and Rumors 05-29-2013, 07:38 PM  
K-3 speculation
Posted By JonPB
Replies: 2,799
Views: 389,571
I agree that the MX-1 is a solid camera release, and the GR an outstanding coup. But I'm not following you: Ricoh should have thought more outside the box, but you use the GXR as an example of them...thinking too far outside the box?

A system camera isn't complex until it comes time to produce a volume of lenses. Ricoh has already shown, with the GXR, that they're happy to use someone else's lenses for their cameras--which makes sense, because cameras are where the money is these days.

I guess I'm not understanding what's so difficult about the "system camera."



I'll never deny that I have a penchant for strong statements. :-)



I have a hard time believing that there exists an oligopoly when it comes to signaling protocol and electrical interface designs for lens mounts--that nobody else could introduce a variant that would withstand legal scrutiny. See, e.g., Sigma's mount.



These points I addressed: that the goodwill is in the used market, which doesn't directly profit Ricoh, and that the mechanical mount is out of patent. Coming full circle: Ricoh could have released a GXR mount for K-AF2 (but not later) lenses, fully compatible with both FA and K/M lenses, without buying Pentax, just like they released a Leica M mount.



Where's the profit in that for Ricoh? Minimal, but I touched upon it. If you don't see that, I'd be happy to expand upon it.

Where's the value in that for us as photographers? Tremendous. The mount is associated with cameras that go back from before I was born until the (hopeful) future, and the lenses span my entire photographic journey so far. I've spent unknown hours thinking about, reading about, and investigating all things Pentax. I'm invested. But that doesn't give Ricoh's business managers any incentive, not one way or the other.

The K-3 will come from Ricoh, not from the fan base. Hopefully there are enough of us to make Ricoh sell the camera we want, but none of us have enough information to determine whether that's the case.
Forum: Pentax News and Rumors 05-29-2013, 04:24 PM  
K-3 speculation
Posted By JonPB
Replies: 2,799
Views: 389,571
To the best of my knowledge, the K-mount has no value; it is a simple design that can easily be copied, and is mostly if not entirely out of patent protection. (The PZ-1p, with the K-AF2 mount, was released 22 years ago.) But your posts are thoughtful and I assume you understand that what Ricoh bought was the Pentax brand--and the loyalty of Pentaxians.

Ricoh also purchased Pentax's other mounts (Q, 645, 67), as well as its lens design expertise and industry connections. The more I learn about the high-end photography market (i.e., kits costing more than $500), the more I think that networking and know-how are what Ricoh purchased.

It is plausible that Pentax had contracts with suppliers (such as for sensors and glass) that made purchasing it worthwhile. I would be surprised if Pentax didn't have sweetheart deals with Hoya. After all, Ricoh might be able to use those contracts for its business imaging products.

Pentax was owned by Hoya, one of the major glass manufacturers. Undoubtedly, Pentax lens designers had an inside glimpse into the Hoya glass projects, and also developed relationships with the people who make the optical glass. If Ricoh was having a hard time interfacing with Hoya, Schott, Corning, or whoever, acquiring those relationships vis-a-vis Pentax--again, not just for photographing imaging uses--would make that acquisition worthwhile.

As an aside, I note that Canon is a major player in both photographic and corporate imaging. I suspect that there is a large crossover in terms of what specialized personnel bring to the table with these markets, something Ricoh lacked before its acquisition of Pentax.

Undoubtedly, the loyalty of Pentaxians is valuable; literally any DSLR that Ricoh might release will have buyers simply due to the Pentax brand. But the numbers are simply unknown. How many Pentaxians does it take to justify a new camera R&D cycle? Probably not enough to justify purchasing the company, or the company would have cost more.

The fact is that most Pentaxians, myself included, were attracted to the brand for its value, which largely hinged on the used market--which is to say, the K-mount. Hoya targeted value-oriented consumers. Ricoh is not. Let me rephrase that: Ricoh, by raising prices, is pushing away the very consumers who represent the bulk of K-mount goodwill. Ricoh is not pursuing what the K-mount brings to the table, although it may well be renewing the K-mount into something better than it ever has been.

What does this all have to do with the K-3? Well: whatever it happens to be, and speculating is less worthwhile now than ever before, will tell us a lot about how Ricoh sees the K-mount. If Ricoh releases a mildly upgraded camera, they will be telling us that the K-mount was secondary to the other sources of value that were offered by Pentax. if Ricoh releases something new and interesting, then they'll be telling us that the K-mount is worth investing in.

At the very least, given Ricoh's track record, I expect the next top-of-the-line K-mount camera to offer an extremely configurable system that experts delight in and which daunts novices. This will be good for those of us who like legacy lenses and geek out with our kit.
Forum: Pentax Film SLR Discussion 05-28-2013, 09:11 PM  
:cool: Lets see those ''film'' shots
Posted By JonPB
Replies: 16,183
Views: 1,876,520
The photo of "Derek" made me look a few times; parts of that could, I swear, be an oil painting. That's something I hadn't seen before. Thanks!
Forum: Film Processing, Scanning, and Darkroom 04-19-2013, 09:47 AM  
Slide copying adaptor vs scanning??
Posted By JonPB
Replies: 14
Views: 5,108
Smigol,

I'm using Cokin filters because they are large and don't have any metal rings that might cause scratches... and also because I was able to buy a bunch of them for fairly cheap. :-) I don't have much experience with filters and assumed that they used numbers in a somewhat consistent way. Oops!

What you're looking for is a way to increase the color temperature of the captured image, so a blue or cooling filter is what you want. I haven't made any attempt to be precise in my filter usage; rather, I just try to get into the ballpark where the Lightroom white balance sliders are sufficient to correct the image. A strong blue filter--022 or 80C?--might be enough on its own to do that, but stacking the weaker 020 and 021 combined works for the Ektar I've shot.

Let me know what you try and how it works!

Cheers,
Jon
Forum: Film Processing, Scanning, and Darkroom 03-30-2013, 09:34 AM  
Slide copying adaptor vs scanning??
Posted By JonPB
Replies: 14
Views: 5,108
To me, it is becoming an issue of end result. Taking careful pictures of every exposure on a roll doesn't make sense when I might only want to print one or two of them. I'm thinking that a loupe would be a good investment to help me decide which exposures I want to invest more time in.

If you're seeing a reflection in the flattening glass, then you have too much extraneous light, which will reduce the contrast of the image. I not only mask out the light source below the negative, but I also do this in a near-dark room (aka on my bathroom floor). Removing most of the unnecessary light has proven to be the single biggest improvement I've yet found.

Also note that negative film is inherently low contrast...which is the flip side of having wide latitude. (Slide film has high contrast and low latitude.) You will normally need to clip the whites and blacks somewhere, or use creative tone curves, to get a desirable level of contrast in the final image.

Personally, I like using my digital camera to capture the negative because it allows me to choose which densities of the negative I want to work with in the digital realm. My view is that as much as possible should be done optically to make the digital bits as meaningful as possible. For example, when I took two pictures of the same negative, one with automatic exposure and one that clipped the highlights of the sprocket holes (exposing to the right), the noise level noticeably favored the latter image.
Forum: Pentax Film SLR Discussion 03-29-2013, 06:37 PM  
:cool: Lets see those ''film'' shots
Posted By JonPB
Replies: 16,183
Views: 1,876,520
Steve,

Unfortunately, I wasn't able to find any good angles of the new bridge, but there's lots of changes happening down at south waterfront if you haven't been there lately. (I'm more of an east side chap myself.)

Cheers,
Jonathan
Forum: Pentax Film SLR Discussion 03-29-2013, 04:32 PM  
:cool: Lets see those ''film'' shots
Posted By JonPB
Replies: 16,183
Views: 1,876,520
I'm only on my third roll of film, which I'm scanning on top of a light table, but maybe this will be useful. Here's my basic setup, from bottom to top:
  • Light table

  • Cardboard mask to minimize light that doesn't go through the negative

  • Filters (020 and 021)

  • Lens hood

  • Negative holder for obsolete scanner with the negatives

  • Macro lens

  • DSLR

  • Tripod


The cardboard mask makes a huge difference in image contrast. I went from using about 40% of my K-5's dynamic range up to about 85% just with this trick. (Rough estimates from looking at the histograms.)

The filters compensate for the orange mask on a negative; you won't need these for slides. They're important for negatives, though, both because they relatively decompress the blue channel (resulting in less digital noise) and because they get the white balance close enough that you can use the eyedropper in Lightroom.

The lens hood is used to move the negative away from the light table, in hopes that any dust or irregular illumination will be blurred out. An inch or two is fine, given that depth of field is very shallow at this magnification.

The negative holder keeps the film flat. This won't be necessary if your slides are mounted.

The camera is suspended from a tripod with the center column inverted. I use a carpenter's level to ensure the light table is level, and a hotshoe bubble level to ensure the camera is also level. If they're both perfectly level, then the sensor plane will be parallel to the film plane.

I'm perfectly happy with my 8x12 print of a 135 negative "scanned" using a Takumar macro (the tricycle shot posted earlier in this thread), but that image didn't have a lot of fine detail in it. The magnification there was a little over 2, so a lot of the frame was cropped. Moving to the tripod gives me the working distance for a 100mm macro and crop-free magnification of about 1.5... and if I want more data from the negative, I can go to a 1:1 magnification and stitch the images together like a panorama.

Here's from today's scanning project (click for bigger)





Forum: Film Processing, Scanning, and Darkroom 03-29-2013, 04:01 PM  
Slide copying adaptor vs scanning??
Posted By JonPB
Replies: 14
Views: 5,108
You actually want a magnification equal to the crop factor, or 1.5 for our APS-C cameras.

I'm still learning how to do this without a scanner, but...

Slide copiers that have adjustable magnification (to get to 1.5) and that can hold your negatives (most of them are designed for mounted slides) would be the quickest way to get the job done. Downside: you're limited to your camera resolution because you can't take a "panorama" at a higher magnification and then stitch those images together.

Current scanners, by most reports, produce very workable images, very quickly. You can get models that scan multiple images at the same time, and focus isn't a problem. Downside: it may be an expensive, single purpose piece of hardware that takes up a bit of room. It, too, cannot be oversampled. Most importantly, though, with color negatives, you will have far less data in the blue channel due to the orange mask.

I use a tripod mounted over a light table to take pictures of my negatives. This allows me to get as high a resolution "scan" as I have the patience for, and also allows me to use filters (a stacked 020 and 021 seem to do the trick) to compensate optically for the orange mask. This also uses the least amount of specialized equipment: tripod, filters, macro lens...these are all things you can use in the field, too. Downside: this takes a lot of time and patience to get right.

I'm still finding ways to speed things up. I use multiple levels to ensure everything is parallel: this is much sturdier than creating a tower of lens hoods for a 100mm macro. My latest innovation is buying a negative holder for an obsolete scanner: the holder was cheap because nobody uses that scanner, but it holds negatives just as well as it ever did. The filters I started using to maximize image quality now get me close enough that I can use the eyedropper in Lightroom then customize to taste.

I'm also aiming to enhance this model by using my laptop as a backlight, and loading up a customized mask for the negative I'm taking to maximize contrast data in the digital realm. Haven't quite started that project yet, though.
Forum: Mini-Challenges, Games, and Photo Stories 03-20-2013, 07:52 AM  
Game Single in April *film only version* Discussion
Posted By JonPB
Replies: 162
Views: 5,754
With film, I've found myself not making any exposures after spending a few minutes looking at a scene, when I would have snapped away a dozen-odd digital captures with my K-5. I like this. I like the contemplation. I think I'm getting better at recognizing interesting scenes.

With these challenges, which I haven't done before, it seems like part of the idea is to just get out there and do it. Practice makes perfect. This balances well against my reluctance to spend money on film.

Here's how I would want to do the Single In April, then. Take pictures every day, with a single lens/camera/film. (Super Program, 35mm/2.8, TMax 100.) Make notes about each exposure. After each day's shooting, I post a description of the capture that I think will be best. This is the daily posting. When I get the film back, I edit that day's post with an image and notes about how it worked better than, worse than, or differently from what I expected.

That kind of project is tailored to what I want to focus on improving--previsualization and using B&W film--but might be more involved than others would be interested in. Thoughts?
Forum: Pentax K-5 03-19-2013, 04:34 PM  
K5 with Fast lenses : Help required
Posted By JonPB
Replies: 5
Views: 1,299
From my limited experience, your A50/1.7 might be very useful here. With F series and newer lenses, the lens provides some information to the camera about what distance is in focus. Without this information, the camera simply has to use its phase detect sensors to determine focus. So using any manual focus lens can help you dial in the accuracy of the AF calibration, especially a fast f/1.7 lens.

I'm assuming that you're using only center point autofocus. If not, the camera could just be choosing the wrong point to focus on. Also, that you're using the green hexagon and not the red square to determine when focus is achieved.

I find it interesting that the 35/2.4 would have worse performance the further away the subject is, and that the zoom would vary between focal lengths. Have you had an opportunity to test this in sunlight?

Finally, I'll commend your observation that the 35mm lens is a lot faster than the 18-250, and I'll add that the K-5 has much more resolution than the K-200. Both of these issues make any AF failures much more apparent.

If I were to narrow down the issue, I'd set up a repeatable test. For example, mount the camera on a tripod (or rest it in a specific location on a stable surface) and test the AF on a high contrast subject that won't move, such as a bookshelf or a building across the street. This way, you can see if there are patterns to the problems, which can help you fix them.

Best of luck!
Forum: Pentax SLR Lens Discussion 03-17-2013, 03:02 PM  
21mm Ltd least exciting Ltd?
Posted By JonPB
Replies: 54
Views: 7,661
If I were to buy the 21, it wouldn't be because it is exciting. "Reliable" would be the word. It would be the lens that I put on my camera when I don't expect to take pictures, so it would be there when I need it. Small and light. Wide enough to get most any ordinary image. Sharp enough to allow substantial crops for snapshots. Image quality that needs no apologies. Complements the 15 (which requires careful composition because it is so wide), and the narrower 40 and 70 (which often disallow the full context of a scene from being in the image). Easier to carry than even the kit zoom, not to mention f/2.8 zooms. Probably not a lens you'd look at a scene and think, "now, what this picture calls for is the 21." But you'd look at pictures taken with the 21 and think, "I'm sure glad I had that kit with me."

Exciting, no. But if I owned all of the Limited lenses, I'd bet that my 21 would have the most wear marks on it. And that'd be a mark of pride.

I should get one.
Forum: Pentax News and Rumors 03-17-2013, 02:39 PM  
Tokina (and Pentax?) 12-28/4
Posted By JonPB
Replies: 15
Views: 5,154
Tokina just announced a 12-28/4 DX lens, which is replacing the 12-24/4.

http://www.tokina.co.jp/camera-lenses/wide-lenses/at-x-12-28-pro-dx.html]AT-...| ????? | ???? (in Japanese)

I'd bet this is the DA wide zoom on Pentax's 2013 roadmap. If Pentax makes it WR, this would be a no-brainer purchase for me.

Haven't seen any English announcements yet, but thought it worth sharing.
Forum: Pentax SLR Lens Discussion 03-17-2013, 12:04 PM  
DA*55 vs K/Tak 55mm
Posted By JonPB
Replies: 23
Views: 2,552
The 55/1.8 is an Auto-Takumar, so with the auto-aperture pin of the Super Takumar, but with reversed aperture settings. Definitely pre-SMC coatings, but not necessarily different from the earlier Super Taks, which had coatings that changed over the years. I believe that the SMC-K 55/1.8 retained the same optical design but with the addition of SMC, whereas the SMC-M 50/1.7 and its successors use a very similar, though slightly simplified and cheaper to produce design. It would be interesting to see a comparison of the K55/1.8 and M50/1.7 to see if any changes are apparent, although I expect you'd have to look very, very closely.




I'll assume that you're laughing in sympathy. :) The camera was anchored on a tripod that I was careful not to move, and focus was checked with live view at 10x magnification. Personally, I'm interested in practical differences. If I'm operating at the maximum ability of the lens/camera combination to focus precisely, and the difference in focus becomes a dominant differentiator between images, then that bit of knowledge is more important than the theoretical differences between the lenses in perfect conditions. But knowing that the images didn't line up perfectly made it easy to decide to only comment on my observations, rather than post the images themselves.



I tried shooting with a 1Ds and I never got the sense that the camera was working with me, although that's probably because I didn't spend enough time for all of its features and operations to become second nature to me. Then again, I've recently started shooting film, and I prefer having controls only for aperture, shutter speed, focus, and shutter release. My shooting style doesn't benefit much from automation. That, combined with slender hands and fingers, makes me happier with smaller, simpler cameras.

Goes to show, I think, that, as far as gear goes, photographers today have an embarrassment of riches in options and opportunities. There will be a close to ideal choice for almost any given set of needs.
Forum: Pentax SLR Lens Discussion 03-15-2013, 06:00 PM  
DA*55 vs K/Tak 55mm
Posted By JonPB
Replies: 23
Views: 2,552
I'm glad to hear it! Canon gear isn't for me--if not due to price, then to size and ergonomics--but it certainly works for other people, and I'm glad both that you're finding better ways to achieve what you want with your photography and that you're willing to contribute to this forum even if you're not shooting with a Pentax anymore. They're all tools and what's perfect for one person would be a horrible choice for someone else.
Forum: Pentax SLR Lens Discussion 03-15-2013, 03:59 PM  
DA*55 vs K/Tak 55mm
Posted By JonPB
Replies: 23
Views: 2,552
You'll note that I was wrong about some things here. :) Lenses have to deal with so many different conditions that keeping track of them is like herding cats. That said, we have so many great options to choose from that it is almost hard to go wrong.



...and almost impossible to go wrong if you have an eye for contrast like Axl has.

{Insert jokingly derogatory comment about Canon because I don't want to know why he walked away from his Pentax kit.} :p
Forum: Pentax SLR Lens Discussion 03-15-2013, 03:33 PM  
DA*55 vs K/Tak 55mm
Posted By JonPB
Replies: 23
Views: 2,552
Today, I have begun to learn just how much of a pain lens testing is.

I found that my DA*55 has some decentering, or at least that the right fifth of the frame is considerably less detailed that the rest of the frame. (I'll note that this lens has scratches from a fall onto a hard surface, so it probably wasn't a manufacturing problem.)

I found that slight misfocus can cause major differences in comparing lenses. Not necessarily in the overall quality of the image, but in telling the difference between two sets of very good optics.

But, as far as this thread is concerned, I'll say that if you don't know whether you want a Takumar 55/1.8 or a DA*55, then you shouldn't waste your money on the modern lens. Even my Auto-Takumar era lens is superb by f/2.8, and throughout its range has less blue glow than any of the SMC lenses I've tried. My DA*55 isn't representative, but it is better in most ways, including contrast, resolution, and bokeh... but the Takumar isn't all that different.

If you don't like the Takumar rendering, you'll probably need to go to another brand of lenses. My Leitz 50mm/2.0 doesn't have the high center resolution of any of the Pentax lenses that I tested--and it pains me to say that a free lens outdoes my $500 lens in any measure, but that's what I've seen. The Leica does, however, render differently. Bokeh doesn't have the thick, green outline; instead, it has a brighter, but much thinner, yellow outline. Bokeh is also harsher with the Leica, although I think this allows the Leica to convey more information about subjects that aren't quite in focus than do the Pentax lenses. Contrast is up across the frame. Overall, when I look at an image from my Leica 50/2, my brain seems to get a better representation of the subject matter than the Pentax lenses conveyed. If I'm shooting an outdoors portrait with lots of distance between the subject and the background, I want a Pentax. If I'm shooting in a close, dark environment, less controlling things than capturing what's happening, I want the Leica. The point being, if your shooting style will accommodate it, you'll probably be better off buying ten $50 lenses in the 50mm range, all from different makes, and picking the right lens for the right shot, than if you buy one expensive lens to do it all.

Because even the cheap Takumars will do it all, and will do so quite respectably.

Anyhow: if I were to have only one Pentax lens for my camera in the 50mm range, it would be the A50/1.4. Full automatic features except autofocus, decent manual focus feel, great performance in middle aperture settings, and a pleasant though gauzy performance wide open.

If I were to also have an autofocus zoom in the 50mm range, I'd go for the Takumar 55/1.8. Better performance wide open without the added color of SMC.

I'll probably sell the rest of my Pentax fifties, including the DA* once it is fixed. It'd be a great lens for portraiture; that's what the lens was designed for. That's just not how I want to use that focal length.
Forum: Pentax SLR Lens Discussion 03-15-2013, 09:00 AM  
DA*55 vs K/Tak 55mm
Posted By JonPB
Replies: 23
Views: 2,552
I've been meaning to compare my fifties, which include the DA 55/1.4 and Tak 55/1.8. The bottom line, though, is that the differences between the lenses aren't very meaningful in photographic terms. I'd recommend an A50/1.7, or DA50/1.8 for autofocus, to anyone who's just looking to make pictures with this length of lens. For absolute value, SMC Takumar 55/2. Personally, I'm overly distracted by minor aberrations that very few other people care about, even if they notice them, and I also am fascinated by the optics and mechanics of camera lenses... but those aren't the same as photography.

Here are my lenses and what I would expect to find in a comparison:
Takumar 55/1.8. Low contrast but sufficient resolution. Good for atmospheric portraiture. Renders veiling glare much like my own eyes, which makes its images more natural and comfortable.
Super Takumar 50/1.4. Similar to the 55/1.8, but with a particular glow or radiance when used wide open.
SMC-M 50/1.7. Solid but not outstanding rendering, in every aspect; which is to say, desirable as a standard lens. Higher contrast than non-SMC lenses, creating an appearance of sharper images. In a word, balanced.
SMC-A 50/1.4. Has the glow of its Super Takumar predecessor, but with much higher overall contrast. Wide open, this lens is all about that glow. Oddly, though technically superior to the Takumar, to me this lens becomes more specialized due to the dominance of that often-desirable aberration.
DA* 55/1.4. Gives what I think of as a modern rendering: where older lenses are desirable for their warm, tender rendering, this lens is desirable for its stark, unfiltered honesty. Basically, this lens' characteristic is that it gets out of the way and lets the subject speak for itself. Plus, remarkably smooth distant background bokeh.
Leica 50/2 (contemporary of the SMC-M line). Avoids the Pentax-characteristic green bokeh fringing. More natural rendering of nearly-in-focus bokeh, at the possible cost of harsher far-from-focused bokeh. Lower contrast than SMC, but likely more center resolution.

But then, I haven't actually done a systematic comparison yet, so that's just my impression. Now I want to see how well my impression matches up with reality. More to come. :)
Forum: Pentax Camera and Field Accessories 03-13-2013, 07:40 AM  
Why do all shoulder straps seem to attach to the tripod mount?
Posted By JonPB
Replies: 53
Views: 15,440
I agree with Lauren that these straps can place the camera at risk, but when I wear mine that's exactly what I want: the risk of damage with its corollary reward of instant camera availability. When shooting in a documentary style, having a camera at one's hand often makes the difference between successful capture and missed opportunity. Now that I'm shooting more contemplatively with still subjects, getting the camera out of the bag hardly affects setup time, so the strap sees less use. Of course, if I'm going for a wander, I'll have the camera on the strap not because it makes it possible to capture the image, but because it encourages me to take a picture when otherwise I might not bother.

As far as secure attachment goes, I used to use a wrist strap that was attached to the left-hand camera strap lug and looped into the strap itself, fully backstoping the tripod-mount system. But I've never found the mount even slightly loose, so I don't do that anymore. (I use an eye bolt, wing nut, fender washer, and felt pad; the wing nut compresses the felt pad, providing a far more secure connection than a simple bolt.)

Why not a neck strap? I never found carrying a camera against my chest to be comfortable. Depending on how it was resting and where my hands were coming from, sometimes I would have the strap under my hands, and sometimes over my hands. I also feel that if someone looks at me, a camera in front of my torso makes more of an impression than one at my side. With a shoulder strap, the strap itself never gets in the way, it is visually unobtrusive, and, if I'm moving around a lot such as scrambling up a hill, the camera stays put with a simple carabiner on my belt. Yes, sometimes the camera on the shoulder strap can flip around, but I frequently have my hands at waist level and the camera provides a convenient hand rest, preventing unwanted movement.

Why the tripod mount instead of the strap lugs? This positions the camera grip under my hand with the lens facing backwards. Not only is this more convenient than having to fuddle about finding the grip, but it also protects the lens from things that I might run into--and I have a habit of paying more attention to things tens of meters away than what's under my nose, so that can be useful. Yes, it prevents quick shifting between tripod and strapped use, but all of my tripod shooting is slow and so that doesn't really make a difference. I can see this being a deal breaker, though, for some people.

For what its worth, I don't see why people use the traditional straps. I would much prefer to have a second tripod mount on the side for an actual tripod plate than to keep the existing strap lugs. At any rate, what different people find comfortable and effective is about as variable as what subjects people like shooting, so there's no wrong answer if what you've got works for you.
Forum: Pentax Film SLR Discussion 03-06-2013, 04:33 PM  
:cool: Lets see those ''film'' shots
Posted By JonPB
Replies: 16,183
Views: 1,876,520
Thanks for the comments.

I'm still learning how to see the color balance. Since I'm using curves to make the adjustments, getting anywhere close to normal looks great after all the odd combinations that your eyes were getting used to. Part of my process will need to be getting it close, then looking at other things for a while before returning to Lightroom. The best trick I've found is to photograph the negative using at least one blue filter to counterbalance the orange mask. Anyone have experience with that?
Forum: Pentax SLR Lens Discussion 03-05-2013, 10:45 AM  
Why not bring back the legendary glass?
Posted By JonPB
Replies: 110
Views: 7,458
I would say that 24mm is expected at the wide angle of any standard, pro-level zoom, which might moot the issue as far as a 24mm Star lens goes.

There was a K 15/3.5 AL, according to Bojidar Dimitrov, which was apparently too expensive to produce; it certainly is legendary, though more for rarity, but we now have much more affordable techniques to manufacture AL lenses. That, and/or a 20/2.8, would certainly complement the wide end of a standard zoom. I have no idea how the 15/3.5 or 20/2.8 perform, though.
Forum: Pentax SLR Lens Discussion 03-05-2013, 10:10 AM  
Why not bring back the legendary glass?
Posted By JonPB
Replies: 110
Views: 7,458
Regarding the FA*24: first of all, I don't think anyone's saying that this lens can't produce good images, or even that it isn't a good lens, just that it doesn't qualify as "legendary glass." I agree with that. It is "historical glass," being one of the first mass produced lenses with an aspherical element, using I believe a resin mold technique that never caught on but which gives the lens a bit of warmth. As far as I can tell, cost-is-no-object Leica didn't release an ASPH lens until 2 years after the FA*24 was released. But I'm not even sure about all of that and such details only matter to collectors, so, onward.

While this post talks about the FA*24 in some detail, I'm really going after what attributes make up a fine lens.



Yes and no. The nisen bokeh is caused by, as you say, bright outlines of bokeh discs, which is overcorrected spherical aberration. But from everything I've seen, the FA*24 has only moderate overcorrection compared to most Pentax lenses, and is no worse than the "reference class" bokeh of the 50/1.4 lenses. I would be willing to wager that the FA 31 adds more color to its bokeh than the FA*24, too, but I went with a red-dot on my 35mm lens so I can't say that for sure.

What the FA*24 suffers strongly from is a contrast between sagittal and tangential resolution. This exacerbates the bokeh outlines for parts of the disc. Here's an example (shot on film).



Look at the disc bokeh in the trees, upper left corner, where you see the sagittal edges (lines from the center to the edge) are brighter but where the tangential edges (lines equidistant from the center) are much better. Together, they create wedge-shaped ugliness, but this shows that the problem isn't purely circular in nature.

The near focus, light color branches are instructive. Toward the center of the frame, there is no double-lined effect, but this arises with some vengeance with the branch extending to the upper left corner (sagittal) about halfway from dead center. Yet on the right side, nearly the same distance from the center, is a branch with what looks like undercorrected (that is, desirable) spherical aberration, but this one is angled away from, not towards, the corner, which is to say that it is positioned tangentially.

I point this out because a legendary lens should have good spherical correction as well as having sagittal and tangential resolution in parity with each other. For example, the FA 43, despite its colored bokeh fringing and lack of edge resolution, has rather harmonious resolution that leads to pleasing rendering.



Curiously, I think that shot shows what I like about the lens. High contrast yet soft. Lends punch to the overall image without pulling the eye away with unnecessary detail.

We can agree, I think, that the FA*24, though not outright bad, doesn't resolve fine detail well enough to be "legendary." That said, the visual effect of an image--which to me is what makes a successful picture--depends on a first impression made by contrast, which tells the story, and only then uses fine detail to keep the mind interested. As the person who was standing behind the shutter when it released, I don't need to be reminded of the broad strokes in the image, so contrast doesn't seem as important; but for someone viewing the picture for the first time, that's the first thing they see. And the FA*24 gives that in gobs.


So, yes, I think Pentax could design a better 24mm lens, and ought to for any 135-frame camera they release. However, given the options for a much larger f/1.4 lens, much slower f/3.2 lens, slower and optically inferior zoom, or many-fold more expensive alternatives, the FA*24 hits quite a sweet spot in the current lineup. What makes the 24 so desirable is how unique it is: there are lots of very good 35s, 50s, and 85s, but only a slow progression in the area of 24s. While I fully intend to keep my FA*24, I would vote for giving us a similar, more modern lens rather than remaking this 22 year-old design.
Forum: Pentax Film SLR Discussion 03-04-2013, 10:54 PM  
:cool: Lets see those ''film'' shots
Posted By JonPB
Replies: 16,183
Views: 1,876,520
A few from my first roll of Ektar. SF1 with 55/1.4 or 24/2.0. Negative processed at the local shop, then photographed with K-5 and S-M-C Takumar 50/4 and finished in Lightroom. Takes a while, but considering this was my second roll of film, the amount I've learned, and the results I'm getting, this is quite worthwhile.









Forum: Pentax SLR Lens Discussion 03-02-2013, 01:34 PM  
Four different 55s
Posted By JonPB
Replies: 15
Views: 1,297
#3 has more coma than the others, and more corrected behind-focus spherical aberration, so I'll call that the Sears.

#1 has lower contrast, so I'll call that the Auto-Takumar.

The SMC Tak and SMC-K have the same optics, and indeed I can't tell the difference. I'll guess that #2 is SMC-K, and #4 is SMC Tak, but that's due to what's most likely a placebo effect in looking for difference in saturation.
Forum: Pentax SLR Lens Discussion 03-01-2013, 08:48 AM  
Why not bring back the legendary glass?
Posted By JonPB
Replies: 110
Views: 7,458
If I were to design a lens, I could take two approaches: one is to start simple, with one or two elements, then add and modify glass to correct aberrations, while the other approach is to find a basic recipe that has already been used and optimize that layout for my particular needs. I suppose my comment about it being relatively easy to update a lens design is in reference to starting de novo, without any reference to other designs. Which nobody would ever do, or could ever do, because they learned how to design lenses by studying what's already out there. For example, even the FA31 was not an entirely new design: it plainly is based on the front grouping of the M35/2 and the rear grouping of the K35/2. That does not imply that they didn't have to recalculate every single surface, not to mention lens assembly. I just think that once you have the basic approach--an outline of the glass and a philosophy to optimize for--then you've already jumped a major hurdle.

But I'm probably being incredibly na´ve, being that I'm definitely quite ignorant of the relative weight of effort required for each part of the process. :)
Forum: Pentax SLR Lens Discussion 02-28-2013, 07:48 PM  
Why not bring back the legendary glass?
Posted By JonPB
Replies: 110
Views: 7,458
A 19/2? No. Absolutely not. I just got back from shooting my 24/2 on film, and that experience will probably push me into buying the DA 15. Wider? No. That is categorically a drug that I do not want to be exposed to.

But this cursed company called "Samyang" will probably do it someday, so Pentax may just as well go ahead and have no respect for my finances but do it right and proper.

:)



I can agree that it isn't one of the all-time greats. If what you're after is edge to edge resolution, then this isn't your lens. Yes, I'd trade my FA24 for an Elmarit-R (II) 19 in a heartbeat. But the 24 renders smoothly and clearly, or my copy does. This is more important to me than resolution in a fast, wide angle lens. In my opinion, the FA24 might not win any lens review awards, but photos shot with it might be more likely to win admiration. If only it weren't so big...
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