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Forum: Pentax SLR Lens Discussion 11-10-2017, 10:52 AM  
FA 35mm 2.0 or DA 35mm 2.8 limited
Posted By ScooterMaxi Jim
Replies: 26
Views: 1,024
Those are stunning photos. The FA 35 is very good overall, but at the close focusing on the cat, I don't think it could quite match the pop of that shot. At normal distances, the FA 35 is very good. Also agree, it tends to be just a bit warm - which might or might not be to your liking. Just as the macro has a reputation for good quality wide open, the FA is good at f/2 and excellent across the entire field by f2.2 - possibly the best lens I have at the aperture. Both lenses are capable of yielding a 3D quality. I don't think there is any question that both these lenses are considerably above average - especially for the price, but their strengths are somewhat different. As an absolute macro (1:2 or closer), I don't think 35mm is a preferable length - especially if you are planning on shooting critters. However, that isn't the main strength of that lens, IMHO, as it clearly performs extremely well as a "normal" lens.
Forum: Pentax SLR Lens Discussion 11-09-2017, 02:41 PM  
What is the most compact/light Pentax zoom lenses?
Posted By ScooterMaxi Jim
Replies: 21
Views: 831
I'm pretty fond of the 28-70 f/4 which is quite a bit smaller than the standard 18-55s though a bit heavier, stronger into the corners (weaker in the center), and renders nicely overall. For a constant aperture zoom, it is pretty amazing for compactness. Balances nicely on the K-01, but the build is a bit of a letdown - compared to the body.
Forum: Pentax SLR Lens Discussion 11-05-2017, 07:55 PM  
Full-frame lens on a crop body not advisable?
Posted By ScooterMaxi Jim
Replies: 168
Views: 4,502
On a more serious note, I do tend to notice some difference in general between crop lenses designed for digital and FF lenses designed for film. You tend to get a snap and saturation with the newer lenses, but a busier look in the near-OOF areas. Especially for landscapes and portraits, I tend to prefer the older, softer look that strikes me as more realistic. This became especially apparent with the DA 50 compared to the older 50s.

Not sure why that would work that way, other than differences in the coatings. One thing I really appreciate with the FF lenses is that they tend to render sharpness similarly on crop across the frame (even though they are likely to have heavier CA on the edges) whereas modern lenses often show considerable sharpness degradation toward the edges compared to the ultra-sharp center. This center-corner sharpness difference is especially apparent in comparing the FA 35 to the DA 35 on crop.
Forum: Pentax SLR Lens Discussion 11-05-2017, 02:33 PM  
Full-frame lens on a crop body not advisable?
Posted By ScooterMaxi Jim
Replies: 168
Views: 4,502
Interesting... I have the Tamron 28-75 lens in Canon mount where it was used both for crop and FF needs. Photozone indicates that the lens performs especially well on crop, but the edges and corners have too many issues for FF. I found that it was really fine at FF when stopped down to f/4, but not adequate wide open (no lens I've owned has dramatically improved so much in a single stop). I'm just the opposite in terms of my shooting needs. I really enjoy lenses that go from wide to mild telephoto - with "normal" roughly in the middle. Starting at normal feels very limiting to me.
Forum: Pentax SLR Lens Discussion 11-05-2017, 01:27 PM  
Full-frame lens on a crop body not advisable?
Posted By ScooterMaxi Jim
Replies: 168
Views: 4,502
Nothing finer than an English cocker for a good excuse; wonderful dogs. It was pretty clear you knew the right stuff, but didn't want others confused.
Forum: Pentax SLR Lens Discussion 11-05-2017, 10:55 AM  
Full-frame lens on a crop body not advisable?
Posted By ScooterMaxi Jim
Replies: 168
Views: 4,502
I'm sure you meant that standing further away "increases" DoF - that is, it becomes less shallow with distance. Otherwise, the point is valid.

What folks tend to forget is that the smaller the sensor the greater the magnification needed. That's where you sense the loss of resolution. Of course, the image circle of a lens has nothing to do with that.
Forum: Pentax SLR Lens Discussion 11-04-2017, 07:23 PM  
The Pentax DA* 11-18mm F2.8
Posted By ScooterMaxi Jim
Replies: 49
Views: 2,172
It's a pre-production model that still has the Tokina markings for a lens introduced more than five years ago. That should help with the LBA concerns.
Forum: Pentax SLR Lens Discussion 10-31-2017, 10:06 AM  
How 'Bad' is DAL 18-55 vs Other Options?
Posted By ScooterMaxi Jim
Replies: 67
Views: 2,042
The right answer comes down to personal needs and what you are willing to spend. The Pentax 18-55 WR is the best value if you need the weather resistance, and are willing to stop down to f/7.1 or more (assuming a good copy). If you need speed (extra light gathering in dim conditions), the Tamron is excellent by f/4, but has a reputation as having less than solid build. I'd be least enthusiastic about the Sigma, but if the slightly extra reach is important to you - worth considering.
Forum: Pentax SLR Lens Discussion 10-05-2017, 08:09 AM  
Opinion needed: DA 40mm f/2.8 - Yes? No?
Posted By ScooterMaxi Jim
Replies: 28
Views: 2,091
Lea, I know a lot of folks swear by that Sigma 30, and are especially fond of it for its sharpness in the center especially. I've seen a lot of fine images taken with it, and much like my Sigma 17-50, it just doesn't impress as much as tests indicate due to the neutral-to-cool coloration and sense of depth somewhat lacking. I like the warmth found on most of the Pentax lenses, even if they might not have the highest sharpness. Also, keep in mind that the Sigma is a somewhat wide angle lens designed only for crop sensors. I would be very surprised if the corner sharpness and light fall off holds up well on full frame.

Others with direct experience might have a different viewpoint.
Forum: Pentax SLR Lens Discussion 10-03-2017, 10:30 PM  
Opinion needed: DA 40mm f/2.8 - Yes? No?
Posted By ScooterMaxi Jim
Replies: 28
Views: 2,091
Well you got in under the two-year limit for responding. The decision was long in coming, but is the right one.

I love my DA 40xs, but see absolutely no reason to try to extend its capability to FF. The body is huge, the little lens is capable on crop, but much like the m40 upon which it is based, not a good choice for FF. You love the FF FA 50, and you would be unsatisfied with the only slightly wider 40mm. The better choices are at 35mm, and the FA35 especially gives you a far better prime step. You will notice a different character to the FA 35, more film like with better bokeh (much like the 40s, but far sharper into the corners). Not as sharp or contrasty in the center compared to any of the 50s, but more natural overall. It might be tempting to go with the DA 35 to save a few dollars, but the FA 35 will be far superior into the corners. Despite the myth forwarded here, the DA vs. FA 35 are not at all similar, especially into the corners (even on crop, let alone FF).
Forum: Pentax SLR Lens Discussion 10-02-2017, 11:15 AM  
Unusual inscription on Pentax-M 50mm f/1.4
Posted By ScooterMaxi Jim
Replies: 10
Views: 640
Back in my camera shop gear selling days around 1980, Pentax (and the other major brands) often provided deeply discounted bodies and lenses sold directly to the retail representatives - for obvious reasons.

Of course, Pentax didn't want to see a black market emerge from these sales, so the inscriptions were the logical move. I went with an LX and m50 f/1.4. I'm sure the SAMPLE inscriptions were also intended to ensure that the sales representatives didn't cycle through stock (mostly a matter discouraging unopened boxes becoming samples). Those reps were displaying and packing up at least once a day.

My biggest issue came with the LX (a body that never got me feeling wowed despite the many pro options available) which had the deeply set inscription right below the shutter cock lever, and due to the softer metal caused some indentation surrounding the heavy scribe. Seeing that I was surprised that it didn't impede the shutter advance. Sure enough, within about four months, the shutter advance mechanism failed - repaired under warranty.

The lens inscription looks much nicer than how the body came out:
http://www.jamesrobins.com/Photo-tests-/M50mm/n-J9JMHR/i-xFMD7rC/A
Forum: Pentax SLR Lens Discussion 09-19-2017, 07:13 PM  
Samyang 85mm f/1.4 or SMC Pentax M 85mm f/2?
Posted By ScooterMaxi Jim
Replies: 63
Views: 2,969
Wow, I thought mine took the cake when it comes to turning a blind eye. Pretty sure I couldn't get away with flashing a 645z without a pointed question. And, if the question was, "What did that cost?" doubt that saying "less than half what the Hassy version costs" would get me out of that pickle.
Forum: Pentax SLR Lens Discussion 09-02-2017, 08:04 PM  
Looking for versatile everyday lens...
Posted By ScooterMaxi Jim
Replies: 41
Views: 1,835
I'd have to wonder if you got a slightly off Sigma 17-50 because there shouldn't be much difference in sharpness between the two when stopped down. Possibly contrast, rendition and saturation favor the Pentax 16-85, but it would be good to know how you get to "greatly outperforms." Personally, for serious landscape work, especially in marginal light, I would rely only on primes. Especially so toward the wide angle side of things, you simply get more consistently sharp results with lower CA issues - and wide zooms tend to have so much field curvature (the major failing of the Tamron 17-50, for instance).
Forum: Pentax SLR Lens Discussion 09-01-2017, 05:11 PM  
Looking for versatile everyday lens...
Posted By ScooterMaxi Jim
Replies: 41
Views: 1,835
Well, we are really speculating based on our own priorities at this point. It isn't clear what the OP wants in terms of IQ, size, lens speed, build and pricing. We're just sharing our particular needs. Norm is absolutely right, assuming that the OP is willing to compromise a bit on IQ, wants low pricing, and seeks considerable reach. Bottom line, there are a lot of good choices out there for mid-range zooms - even in Pentax.

It is entirely possible that we have provided a bit more feedback than the OP is wanting to process. Might be best to say look at the lens reviews on this site, but narrow choices based on needs before you look at all those options.

I want the one that is really small, super fast, plenty of reach, excellent build and extremely high IQ at a very low price. Can hardly wait until that one shows up.
Forum: Pentax SLR Lens Discussion 08-31-2017, 08:32 AM  
Looking for versatile everyday lens...
Posted By ScooterMaxi Jim
Replies: 41
Views: 1,835
Although I don't own one, I agree overall with the sentiment regarding the 16-85 given the high quality of the images it produces. It doesn't work well for me due to the size and relatively slow aperture. I have the Sigma 17-50 (even a bit larger) and find it performs well in pretty much every situation - especially so toward wide open. Brooke is right about the Tamron 28-75 (having shot it extensively on Canon both FF and crop), but it isn't a single lens solution on a crop camera; it also isn't as strong wide open as the Sigma (but is excellent already by f/4).
Forum: Pentax SLR Lens Discussion 08-30-2017, 07:23 PM  
How does stopping down the lens move the focus point forward/backward?
Posted By ScooterMaxi Jim
Replies: 6
Views: 593
It seems that the fast 85s are the Nirvana of challenging focus shift experience, but all lenses have some form of focus shift (no matter how minor). The main criticism of the Zeiss Planar, Nikon, and even the lowly Samyang 85 designs are entirely consistent - focus shift is a factor requiring (minor) compensation. Work within the limitation. Stop down to focus precisely accordingly. Use live view magnification for precision stopped down focusing for exacting results, and understand that a very limited range of apertures have a meaningful impact. From f/4 and beyond on a crop sensor (f/5.6 for FF), the DoF eliminates the need for absolute precision related to focus shift.
Forum: Pentax SLR Lens Discussion 08-07-2017, 09:00 AM  
Don't swear off your lens until you try this trick
Posted By ScooterMaxi Jim
Replies: 11
Views: 1,010
A common mistake shooting landscapes with an UWA (14mm and wider on crop, and 21mm or wider on FF) is that the lens designs tend to have considerable field curvature. Even moderate wides, such as the Tamron 17-50, can have extreme field curvature at the wide end. So, shooting at no less than f/11 will yield the sharpest results more evenly, and f/16 is often optimal.

Another major concern, especially when shooting faster lenses, is focus shift. The Samyang 85mm f/1.4 shows considerable focus shift in the f/2-3.6 range, so critical work demands focusing with the lens stopped down. Past about f/4 the DoF pretty much eliminates the issue.

Understanding the limitations of a lens and the situation is a big part of the process of getting the best images.
Forum: Pentax SLR Lens Discussion 08-03-2017, 09:43 AM  
Lenscore.org is good, but they are NOT perfect
Posted By ScooterMaxi Jim
Replies: 25
Views: 1,318
I agree with Norm to a point on this one. Those of us who have an interest in this conversation see the overall tendency to value chart sharpness over character because the numbers are easily understood. Even if you could reliably measure bokeh quality (doubtful) most lenses have bokeh strengths and weaknesses that change with aperture and amount of out of focus. The variables become exponential. Many of us find near focus on the modern high contrast lenses quite distracting and unnatural looking (DA 50 comes to mind). Others like that look.

Then there is the overall usefulness of a lens for specific purposes. As the testing here shows, the 60-250 lens considerably outperforms the 55-300s in optical testing, but if you do a lot of action shooting - you are far better off with the latter lens. I picked up an FA 28-70 f/4 lens that isn't very sharp but renders nicely - and works well for street shooting grab shots because it is so small. If you want stealth for candids and need some reach, I can't think of a better option - even though it isn't optically near the top.

It is important to gather information from several sources, both qualitative and quantitative information have value. As a group, many Pentaxians tend to value qualitative aspects more which accounts for the fondness for old Taks and Limited lenses that often aren't near the top in IQ ratings, but have unusual characteristics. It also likely accounts for rather unenthusiastic responses toward the large zooms that accompanied the K1 introduction despite their high IQ ratings.
Forum: Pentax SLR Lens Discussion 07-31-2017, 07:15 PM  
K-70 Rear converter and 55-300 PLM
Posted By ScooterMaxi Jim
Replies: 20
Views: 1,050
I guess there is a market for everything, and what "works" as opposed to what gets you good macro results is a pretty vast expanse.

Serious, consistent macro on the Pentax system requires manual focusing. An older Pentax MF macro will be an economical, quality option that will far outperform any of the consumer lenses and TC mentioned in this thread. Heck, even B+W photo diopters on a Pentax prime lens will outperform any of the consumer zoom + TC combos mentioned. And anyone who even tries to mount a TC on a 4.5-6.3 zoom (PLM) for macro work really must believe that monkeys type the works of Shakespeare - as that is just how likely the subject will achieve sharp focus - AF or MF.

Even on the most capable AF systems, committed macro users opt for MF. I guess someone needs to post a 20-minute video explaining how to manual focus a lens on Pentax.
Forum: Pentax SLR Lens Discussion 07-28-2017, 01:17 PM  
How many tilt shift lenses are available?
Posted By ScooterMaxi Jim
Replies: 21
Views: 727
Agree with you that anyone serious about shift lenses is not well served by the alignment and tolerance issues introduced by an adapter...

So, AFAIK, the very old Pentax K28 Shift and the current Samyang/Rokinon 24 Tilt/Shift are your only direct K-mount options. Both are considered good for their designated purpose, but probably not quite exceptional. Keep in mind that the Samyang/Rokinon will give you full A lenses metering capability - if that is a consideration for you.
Forum: Pentax SLR Lens Discussion 07-28-2017, 12:51 PM  
70-300 lenes
Posted By ScooterMaxi Jim
Replies: 20
Views: 1,035
The Tamron and Sigma models you have are not digital era designs - so considerable CA issues are very evident, especially on the long end (Sigma has a newer APO design that is somewhat better). The Pentax 55-300 4-5.8 is definitely sharper than the third party offerings in the 250-300 range. However, the much lower CA is probably even more noteworthy because even the best RAW converters can't remove massive CA without resulting image degradation. While the non-PLM 55-300s are optically similar, the WR version has a better build more likely to hold together than earlier builds and HD coatings yield a very slightly higher contrast.


While the 60-250 is a very good optic, keep in mind that severe focus breathing reduces reach considerably even at medium distances (20-40 feet or closer). Focusing is very slow. The lens will not perform as well overall as the 55-300 when shooting wildlife, and is not adequate for shooting birds in most situations.
Forum: Pentax SLR Lens Discussion 07-19-2017, 04:25 PM  
Which 35mm lens? (DA 35/2.4, FA 35/2, DA 35/2.8 Macro)
Posted By ScooterMaxi Jim
Replies: 49
Views: 2,300
In my photo store selling days (extending to before AF), I recall a few lenses without rear coatings. Some Minolta kit lenses, if I recall correctly. Even low line Tokina wide angle and basic zoom lenses had at least one rear coating. Looks like the Pentax FA 28-70 has only one rear coating. Even my Zenitar has multi-coatings (and a good coating on that required rear filter element). Other than that, all my film era lenses have multi-coatings behind the diaphragm and certainly appear to have them on the rear element. It might just be a matter of the lenses I've run across (there are quite a lot of them). Beyond the sensor reflection issue, it is good practice for the sake of light transmission and better contrast even on otherwise middling consumer lenses.

---------- Post added 07-19-2017 at 06:36 PM ----------



I didn't mean to infer that it wasn't a good lens. In fact, I pointed out that it is better in the distortion department, likely better coatings and contrast. In short, it pretty clearly has a more modern look oriented toward digital preferences. Those aren't really my preferences, but that just would be me. Even the plastic mount is not an issue, as long as the build quality is good and solid (the DA 50 is fine with me). Certainly the DA 35 has had fewer build issues than, say, the SMC 21 which is all metal yet prone to loosening problems. I just keep my fingers crossed.
Forum: Pentax SLR Lens Discussion 07-18-2017, 10:07 PM  
Which 35mm lens? (DA 35/2.4, FA 35/2, DA 35/2.8 Macro)
Posted By ScooterMaxi Jim
Replies: 49
Views: 2,300
So, we have it... They share an awful lot in common regarding the optical groupings and diaphragm design. They are just slightly different because the FA has less light fall off, the front objective is larger, it is a half stop faster, resolution is more consistent edge-to-edge wide open, the coatings are different (by most reports), metal ring, physical aperture ring; the DA has less measured distortion, is considerably lighter, and has greater contrast (by most reports). Other than the several fairly significant physical and imaging differences, they are quite similar. Certainly more similar than the macro, but we have a pretty good idea that they are not essentially similar.
Forum: Pentax SLR Lens Discussion 07-18-2017, 08:14 AM  
Which 35mm lens? (DA 35/2.4, FA 35/2, DA 35/2.8 Macro)
Posted By ScooterMaxi Jim
Replies: 49
Views: 2,300
Now I see even the schematic is somewhat different - though nothing in the schematics tell us differences in glass or coatings, and the point that the claimed schematics are similar was never contested. Look a bit more closely (not that it really matters). We have measured the front elements and the rear elements - showing very clearly that the ratios are different. Yep, undeniable facts.

---------- Post added 07-18-2017 at 10:43 AM ----------



Well, they aren't similar. Regarding the light fall off, Simon indicated that FA was at 9% at f/2.8 (one stop down); the DA indicated 22% at f/2.4 (wide open), and 11% f/4 (1.5 stops closed). This isn't terribly surprising when you consider that the front objective is around 20% larger! I don't know about warmer, but we have generally seen higher micro contrast in the DA lenses. Possibly mostly related to their newer design.

The sharpness argument on the edges would be more debatable based on sample variation. However, for those of you who read these thorough Lenstip tests, we always get clues about copy quality in the Astigmatism/Coma section. The DA had virtually no corner coma (although Simon was a bit brutal in pointing out that plastic mount lenses often don't hold together well over time and heavy use). The FA had a pretty healthy dose of corner coma not shown in the center, indicating (most likely - all other things being equal) that the lens was slightly decentered. Yet, the FA was the stronger edge performer, especially wide open. I am sure the DA is adequate on the edges, but the FA is really impressive in this regard (keeping in mind that the edge of crop is a long ways away from a FF edge).

I'm just going by the known facts. You would really have to attack the testing methodology of Lenstip to win this argument (claiming that the lens performance is essentially similar), but the light fall off side of it is an especially simple measurement that is not subject to much in the way of sample variation. And that light fall off differential is significant.
Forum: Pentax SLR Lens Discussion 07-18-2017, 02:48 AM  
Which 35mm lens? (DA 35/2.4, FA 35/2, DA 35/2.8 Macro)
Posted By ScooterMaxi Jim
Replies: 49
Views: 2,300
All are agreed that the schematic of the two lenses are similar, and - of course - neither lens has issues with the flat rear element design that can contribute to sensor hot spots and other issues. The idea that the FA 35 - one of the more respected lenses of that era - would not have back coating is just a bit breathtaking. You seem to have no idea about the lens. (The lens tests out fairly well for work against the light - I just find its performance not up to expectations compared to its overall strengths.) In any event, a close inspection of the FA 35 coatings show it to be very different from the DA 50, DA 40xs, SMC 21, and I could go on and on. The coatings regimen for zoom lenses is entirely different than for prime lenses, so let's not be mixing our pudding with Jello.

Finally, for those who are willing to look at the extensive reviews done by Simon at Lenstip 13 months apart entirely on crop sensor bodies, I will rest my case. Highlights include that the DA 35 has best in class distortion, and the FA 35 ranked middle of the pack when tested against various other 35s (Canon, Nikkor). Light fall off testing showed the FA best in class (fairly easily) while the DA trailed the Nikkor by a wide margin; at f/2.8 testing shows FA fall off 9%, DA fall off 22% (crop sensor designation for good reason). Take care in comparing the resolution and CA numbers from one lens to the other because different sensors were used, but the characteristics are not similar - as the center and edge resolutions wide open are very similar on FA (impressively so), while the DA is sharper in the center but the edge is much weaker; most users of both lenses also tend to note this.

Bottom line, these are two considerably different lenses and the myth that they are optically similar does not square with the facts. And that isn't even taking into account the vast physical differences.
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