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03-11-2019, 03:10 PM - 3 Likes   #16
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I needed to spend some time with this lens to get it to gel with my kind of photography which is landscapes with a tripod. With my 24mm (Samyang) I can fold the legs of the tripod to a very low setting and have good results. With the Irix was plagued with the edge distortions already mentioned. But with the legs folded in the upright position that problem went away. And with such a wide lens I becomes very tricky not to photograph your own shadow! My biggest problem to date is with the Irix 10 stop ND filter for long exposures. Even though it is a rather thin filter there is very pronounced vignetting and is very easy to get weird spots on the glas that are rather difficult to get rid of. I do shoot a lot near and above salt water and I store my filters in a dedicated pouch. I never had any problems with my B+W filters but I returned one Irix filter for a warranty repair and bought another one that is displaying the same kind of problems. I have yet to try the repaired filter. But the lens itself is really good. Infinity is where it should be and the option to lock the lens on infinity is helpful. And I can get close up enough to objects in my foreground to create some depth in my photo's without losing critical sharpness. It does not deal with as well as some of my Pentax lenses with shooting into the sun but I can work around that. One recent example...



03-11-2019, 07:27 PM   #17
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QuoteOriginally posted by Fries Quote
I needed to spend some time with this lens to get it to gel with my kind of photography which is landscapes with a tripod. With my 24mm (Samyang) I can fold the legs of the tripod to a very low setting and have good results. With the Irix was plagued with the edge distortions already mentioned. But with the legs folded in the upright position that problem went away. And with such a wide lens I becomes very tricky not to photograph your own shadow! My biggest problem to date is with the Irix 10 stop ND filter for long exposures. Even though it is a rather thin filter there is very pronounced vignetting and is very easy to get weird spots on the glas that are rather difficult to get rid of. I do shoot a lot near and above salt water and I store my filters in a dedicated pouch. I never had any problems with my B+W filters but I returned one Irix filter for a warranty repair and bought another one that is displaying the same kind of problems. I have yet to try the repaired filter. But the lens itself is really good. Infinity is where it should be and the option to lock the lens on infinity is helpful. And I can get close up enough to objects in my foreground to create some depth in my photo's without losing critical sharpness. It does not deal with as well as some of my Pentax lenses with shooting into the sun but I can work around that. One recent example...
Fries: That is a tremendous image. I notice the distortion on the IRIX also. I bought a Fotasy UV Haze filter that seems to be ok. I don't have experience with the IRIX filters but I usually go with B&W, Hoya or Tiffen (Made in the USA) and have little "add on" to the image. I bought the Fotasy because I was having trouble finding the size for the IRIX (a huge lens) and certainly, not easy to handle in a hand-held situation even with the K-1's extra 5 step Shake Reduction.

The fact most of us contributing to this thread have had to "deal with" aspects of the lens makes it less than ideal for virtually anything except tripod use. That's a shame because having a 15mm wide prime that is portable was my hope for this lens.
03-11-2019, 08:20 PM - 1 Like   #18
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QuoteOriginally posted by Merv-O Quote
Fries: That is a tremendous image. I notice the distortion on the IRIX also. I bought a Fotasy UV Haze filter that seems to be ok. I don't have experience with the IRIX filters but I usually go with B&W, Hoya or Tiffen (Made in the USA) and have little "add on" to the image. I bought the Fotasy because I was having trouble finding the size for the IRIX (a huge lens) and certainly, not easy to handle in a hand-held situation even with the K-1's extra 5 step Shake Reduction.

The fact most of us contributing to this thread have had to "deal with" aspects of the lens makes it less than ideal for virtually anything except tripod use. That's a shame because having a 15mm wide prime that is portable was my hope for this lens.
Thanks! The size of the lens in this case isn't the reason I use a tripod; I am happy to use the DFA150-450mm hand held for my work. It is just a good idea when shooting landscapes with the mirror up to get the most out of any given lens. And when shooting with long shutterspeeds there is no other option.
03-12-2019, 12:21 PM - 3 Likes   #19
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I think that you're asking too much of just one lens. Most lenses are corrected for infinity and perform accordingly worse the closer you get, unless they have very complex focusing mechanisms with "floating elements" or group focusing. Zeiss lenses are certainly built that way and is the reason why the K 28/2 also performs so well at all distances. Most lenses just focus by moving the whole optical assembly away from the film/sensor plane. The Irix has rear group focusing, which is excellent for weather sealing, since less external parts are moving relative to each other which could promote water transport through those surfaces, which I think is great, because many great lenses aren't weather sealed, and in this case I don't have to worry about it getting wet under the rain on some hike, except for the water beads that get in the way of the picture.
All lenses have pros and cons, and I think this one's got a lot of pros.
+ Weather sealed
+ f/2.4 for anything indoors and after dark.
+ Focus lock, infinity adjustment, infinity stop with ability to go beyond in extreme temperature cases where focus shifts.
+ Ability to use filters

- Weight perhaps since I have the Blackstone version, but it's f/2.4 and not f/4, so… maybe Pentax should have a 15-30/4 with filter ring.
- Manual focus, but that can be a waste, too from what I've learned from my experience with the smc DA 15/4 (which also isn't WR) since I have to focus it on the corners in live view because of its strong field curvature.

So, and as far as macro lenses go, thay are corrected to perform best at certain magnifications. Perhaps just 1:3 to 3:1 or 1:inf to 1:1 and you have to turn them around to use them for greater than 1:1 magnifications. That being said, I think you should try out the Laowa 15/4 macro. Maybe it's a good middle ground and great to use for architecture on your K-3ii.

I would also suggest you show us with pictures what you're exactly talking about. Is it perhaps the chromatic aberrations at close distances? Can they be fixed in pp software? I think most of it should be able to be corrected.

One last thing, I warn you, that although it's a UWA lens, it's depth of field at close distances is way thinner than you might think, and things in the viewfinder look too small as to discern correct focus, so a tripod (not just a monopod) and absolutely still subjects are essential.
For less than still subjects there's always the option of continuously shooting while slowly turning the focus ring.

Remember to post some pictures so we can get a better idea of what bothers you.

03-13-2019, 06:34 AM   #20
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QuoteOriginally posted by torashi Quote
I think that you're asking too much of just one lens. Most lenses are corrected for infinity and perform accordingly worse the closer you get, unless they have very complex focusing mechanisms with "floating elements" or group focusing. Zeiss lenses are certainly built that way and is the reason why the K 28/2 also performs so well at all distances. Most lenses just focus by moving the whole optical assembly away from the film/sensor plane. The Irix has rear group focusing, which is excellent for weather sealing, since less external parts are moving relative to each other which could promote water transport through those surfaces, which I think is great, because many great lenses aren't weather sealed, and in this case I don't have to worry about it getting wet under the rain on some hike, except for the water beads that get in the way of the picture.
All lenses have pros and cons, and I think this one's got a lot of pros.
+ Weather sealed
+ f/2.4 for anything indoors and after dark.
+ Focus lock, infinity adjustment, infinity stop with ability to go beyond in extreme temperature cases where focus shifts.
+ Ability to use filters

- Weight perhaps since I have the Blackstone version, but it's f/2.4 and not f/4, so… maybe Pentax should have a 15-30/4 with filter ring.
- Manual focus, but that can be a waste, too from what I've learned from my experience with the smc DA 15/4 (which also isn't WR) since I have to focus it on the corners in live view because of its strong field curvature.

So, and as far as macro lenses go, thay are corrected to perform best at certain magnifications. Perhaps just 1:3 to 3:1 or 1:inf to 1:1 and you have to turn them around to use them for greater than 1:1 magnifications. That being said, I think you should try out the Laowa 15/4 macro. Maybe it's a good middle ground and great to use for architecture on your K-3ii.

I would also suggest you show us with pictures what you're exactly talking about. Is it perhaps the chromatic aberrations at close distances? Can they be fixed in pp software? I think most of it should be able to be corrected.

One last thing, I warn you, that although it's a UWA lens, it's depth of field at close distances is way thinner than you might think, and things in the viewfinder look too small as to discern correct focus, so a tripod (not just a monopod) and absolutely still subjects are essential.
For less than still subjects there's always the option of continuously shooting while slowly turning the focus ring.

Remember to post some pictures so we can get a better idea of what bothers you.
Great post.
03-13-2019, 11:20 AM   #21
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QuoteOriginally posted by texandrews Quote
Great post.
Torashi's review was really good....outstanding analysis actually. Let's all take some IRIX 11mm of 15mm photos and attach them for review. I'll attach it to my K-1 this weekend and do awalkaound
03-14-2019, 09:15 AM   #22
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Thank you guys for the kind words. I'd like to point out another nice design feature. The filter window is truly a perfection of the Pentax design. How many ads have I (and most of you) seen of Pentax lenses with a hood that's missing that one piece? Then again, in this case, only relevant to people using very rare 95mm filters instead of square ones.
That being said, I tried out the lens wide open with my IVb center filter (for a Schneider 72mm XL) in order to remove vignetting, and funnily enough, it works beautifully. XD

03-17-2019, 02:53 AM   #23
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QuoteOriginally posted by Merv-O Quote
...
The fact most of us contributing to this thread have had to "deal with" aspects of the lens makes it less than ideal for virtually anything except tripod use. That's a shame because having a 15mm wide prime that is portable was my hope for this lens.
I've only felt I had to use a tripod because of a slow shutter speed (photographing the astral plane). Almost all the pictures I've taken with that lens have been hand-held with what I thought were dandy results.

03-17-2019, 02:58 AM   #24
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QuoteOriginally posted by torashi Quote
....
agree completely, and I'd add that the Irix prime is suitable for full-frame use - the best lens Pentax had available when I bought mine that I thought was equivalent was an APS-C zoom (HD Pentax-DA* 11-18mm F2.8) that cost a whole lot more money.
03-17-2019, 07:58 PM - 1 Like   #25
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QuoteOriginally posted by dlh Quote
agree completely, and I'd add that the Irix prime is suitable for full-frame use - the best lens Pentax had available when I bought mine that I thought was equivalent was an APS-C zoom (HD Pentax-DA* 11-18mm F2.8) that cost a whole lot more money.
dlh: I'm not saying the IRIX is a bad lens, just not satisfied with how it performs for me. Unfortunately, no one would rent me an IRIX (most people have never heard of the brand) so I bought it, untested and untouched until received. The photos don't do it justice, it is a big boy, but I hope to use it for landscapes later this year on a tripod.
03-22-2019, 09:26 AM   #26
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QuoteOriginally posted by torashi Quote
Thank you guys for the kind words. I'd like to point out another nice design feature. The filter window is truly a perfection of the Pentax design. How many ads have I (and most of you) seen of Pentax lenses with a hood that's missing that one piece? Then again, in this case, only relevant to people using very rare 95mm filters instead of square ones.
That being said, I tried out the lens wide open with my IVb center filter (for a Schneider 72mm XL) in order to remove vignetting, and funnily enough, it works beautifully. XD
Torashi, as requested here a few random pics from the IRIX 15mm....
Attached Images
View Picture EXIF
PENTAX K-1  Photo 
View Picture EXIF
PENTAX K-1  Photo 
03-22-2019, 01:39 PM   #27
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QuoteOriginally posted by Merv-O Quote
Torashi, as requested here a few random pics from the IRIX 15mm....
Ok, can you please tell us more? I want to know what you are seeing in those pictures. It might be different from what I see.

I can't see the EXIF data on my phone. If you could include the info (mainly aperture used), that would be very helpful.

Please read this after the above:
It's really hard to judge a lens if I can't handle it and take it through some paces aka stress tests. What I can see and tell you, is that at larger apertures, the depth of field is thinner than you think. Even if it's an UWA (which makes it even harder since everything is so small across the viewfinder). I've noticed this with mine. If I don't absolutely nail focus, it will show. A viewfinder magnifier and/or live view are immensely helpful.
Also, check your mount. There is one design flaw. I though mine was misaligned since one side was blurry. Turns out the mount only has three screws vs. five Pentax always uses. So mine got unscrewed, so I solved it with a tiny bit of thread locker before I screwed them back in tight (but not too tight!).

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