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08-18-2014, 01:06 PM   #811
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QuoteOriginally posted by Nicolas06 Quote
yeah agree, that also the problem of 70mm f/2.4... A good zoom cover it too. But the prime could be perfectly sharp wide open, with perfect constrast, good color rendition and no flare. This no zoom will do. And for the flare a 24mm f/1.4 prime will not do neither.

See the example of that 35mm f/2.4 plastic wonder of pentax. It perform a littke better at f/2.4 than the Sigma 35mm Art at f/4 on borders... (APSC both) even through the sigma was tested on the nikon with a sensor that has slightly better max MTF. Chromatic aberations are better handled. The Sigma Art as rounded blades and that help a lot but it get onion bokeh too and that not good. Both tend to outline the higlight, at least on APSC...

Compared to the 30mm f/1.4 Art of sigma, well the sigma doesn't approach at f/8 the border quality the DA35 f/2.4 has at f/2.4...

Getting modest characteristics can help sometime.

I fully agree that there is sense for an f/1.4 35mm on FF. For a 24mm, honestly, I don't think that really that usefull.
[RANT]
No, no you can't be right. That slow dog has only f/2.4 so it is slooooow as a disabled dog on an old 1/2.3" sensor.
Bad idea, bad idea. If it isn't f1/.4, it is slow, you get that?
We don't get a sh*t about quality and rendering... just sharpness, ridiculous DOF and speeeeeeeed !!!!!
[/RANT]

Sorry.. just wanna make some fun (and no, I don't fully subscribe to my rant... this is just a rant after all..)
[/RANT]

08-18-2014, 01:32 PM   #812
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QuoteOriginally posted by D1N0 Quote
The Sigma Super-Wide II is a nice cheap 24mm alternative for pentax. You still see it pretty often on ebay. I have the MF version and I think it's great. Sigma AF 24mm f/2.8 macro (Pentax K) - Review / Lab Test Report
Me too, wide open it is fantastic!
08-18-2014, 01:35 PM   #813
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QuoteOriginally posted by ElJamoquio Quote
Good points. Personally I love the 15mm F/4 because of it's size and it's lack of flare (and other benefits, too). It's a great lens even though there are zooms that exceed it in capability, stats-wise.

However, the fact that a lot of zooms are much more flexible, both in focal length and aperture capability, mean that the 15mm is relegated to a 'specialty lens', that perhaps most people* would pass by.

I actually have a lens like the one you're describing, kinda. I have a Zeiss 25mm F/2.8. Beautiful pictures come out of it... but it's neither small nor light.

(*Most people do not spend a lot of time on a Pentax-based web forum).
Yes that's sure ! A 24mm f/2.8 is difficult to sell. But I'am not sure you get many client for a 24mm f/1.4 that is going to be as big as the zoom, very expensive and not more sharp. The Canon version is really garbage at f/14 with 3EV vigneting and absymal border performance. Like it was more an f/2 design (still 2EV vigneting and bad border performance at f/2).

The Nikon look fine on the spec sheets, but you need to put some use out of it.
08-19-2014, 09:09 AM - 1 Like   #814
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QuoteOriginally posted by monochrome Quote
Is that lens not rumored to cover a larger image circle? Could it not become an HD DA Pro 200/2.8 (meaning FF image)? Same story with DA*300?
There's an old Japanese lens roadmap where the DA* 200 and DA* 300 lenses are listed as "DFA" glass.

QuoteOriginally posted by mecrox Quote
I'd like a return to beautiful rendering and focus transitions, away from the current mania for sharpness above all else.
I agree. The trouble is, how do you sell an expensive lens on the basis of rendering, focus transitions, color rendition, and microcontrast when nearly all reviewers, on both the internet and in print, care only about sharpness, distortion and CAs? The gearheads, with all their physics-envy inspired math, have won on this issue.


Last edited by northcoastgreg; 08-21-2014 at 07:02 AM.
08-19-2014, 09:26 AM   #815
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QuoteOriginally posted by northcoastgreg Quote
agree. The trouble is, how do you sell an expensive lens on the basis of rendering, focus transitions, color rendition, and microcontrast when nearly reviewers, on both the internet and in print, care only about sharpness, distortion and CAs? The gearheads, with all their physics-envy inspired math, have won on this issue.
That really is an issue - borne of our global culture's manic need to measure, sort, rank and score everything. Sharpness, distortion and CA's can be measured (relatively) objectively (if there was a universal mount so lenses could be compared on a standard sensor and camera).

The real problem, though, comes when popular fashion appreciates only the edge-to-edge sharpest images. It is one thing for a discerning lens buyer to have a different appreciation set and for a lens maker to appeal to that difference. It is another matter entirely for a photographer to sell prints that display those different image qualities.
08-19-2014, 09:33 AM   #816
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QuoteOriginally posted by D1N0 Quote
The Sigma Super-Wide II is a nice cheap 24mm alternative for pentax. You still see it pretty often on ebay. I have the MF version and I think it's great. Sigma AF 24mm f/2.8 macro (Pentax K) - Review / Lab Test Report
This is a great suggestion, its a cracking little lens, its tiny, sharp wide open, close focus.

This is the kind of thing I would like to see, that's the only downside I see with the more modern Sigma Lenses, they are all massive.
As an example, the Pentax FA 20-35 f4 compared to the Sigma 20-40 f2.8 is no competition, yes the Sigma is faster but its also well over twice the weight and much bigger!
08-19-2014, 09:51 AM   #817
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QuoteOriginally posted by northcoastgreg Quote
There's an old Japanese lens roadmap where the DA* 200 and DA* 300 lenses are listed as "DFA" glass.



I agree. The trouble is, how do you sell an expensive lens on the basis of rendering, focus transitions, color rendition, and microcontrast when nearly reviewers, on both the internet and in print, care only about sharpness, distortion and CAs? The gearheads, with all their physics-envy inspired math, have won on this issue.
I completely agree on the aesthetic merit of a lens but the hard fact is that it is nearly impossible to measure and compare along with the reality that "beauty" has many interpretations. The optical physics and related effects can be measured and compared between different lens's. That's really the only objective measurements we have to work with.
08-19-2014, 10:59 AM   #818
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QuoteOriginally posted by woodywesty Quote
I completely agree on the aesthetic merit of a lens but the hard fact is that it is nearly impossible to measure and compare along with the reality that "beauty" has many interpretations. The optical physics and related effects can be measured and compared between different lens's. That's really the only objective measurements we have to work with.
Yep but it doesn't mean those are the only measurements we should work with.
Nobody would review a car sticking only to the specs sheet. Otherwise, PDF download from the manufacturer's website is a review.

08-19-2014, 11:27 AM   #819
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QuoteOriginally posted by woodywesty Quote
I completely agree on the aesthetic merit of a lens but the hard fact is that it is nearly impossible to measure and compare along with the reality that "beauty" has many interpretations. The optical physics and related effects can be measured and compared between different lens's. That's really the only objective measurements we have to work with.
Review now include bokeh comparison. To be honest this is really basic but they look at the shape of the circle highlight, if there is oinion bokeh, if there is an outlining and they say if it buzy or smooth. Example if photozone.

Few include MTF20 that are more representative on actual micro contrast on top of MTF50 that is fine sharpness (the thing you need to look at crops to notice).

There is no serious discussion through on constrast, color rendition, hability to get 3D pop (or pixie dust) and qualities of rendering transitions.

While it is very possible to test scientificaly, I never see color accurary graphs except from DxOMark. Contrast is not tested scientifically neither while it could.

I remember an article explaining that when the FA ltd where designed, the design included non fully corrected focus plan as a feature as they recognised that in practice it allowed to get more pleasing image to the eyes. Thoses FA ltd are really made to get the best images. Not to get the best tests result. Even through FA31 has a stellar performance, even on charts.
08-19-2014, 11:41 AM   #820
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QuoteOriginally posted by monochrome Quote
That really is an issue - borne of our global culture's manic need to measure, sort, rank and score everything. Sharpness, distortion and CA's can be measured (relatively) objectively (if there was a universal mount so lenses could be compared on a standard sensor and camera).

The real problem, though, comes when popular fashion appreciates only the edge-to-edge sharpest images. It is one thing for a discerning lens buyer to have a different appreciation set and for a lens maker to appeal to that difference. It is another matter entirely for a photographer to sell prints that display those different image qualities.
I was trained as an engineer, and one thing you quickly learn is to look for the pros and cons of any design choice. It would be fascinating to listen to an optics designer. When one designs purely for sharpness, what do you give up instead? I don't know the answer to that, but perhaps it means more optical elements which translates to lower transmission or some such con.

In defense of the consumer, when it comes to putting out a $1000 or $5000 or $10,000 for a lens, one wants to be sure that its money well spent.

I'm a member of an art gallery, and its interesting to hear what painters consider important compared to what photographers consider important. What i find interesting is watching visitors walk down a display of paintings and photographic art, and seeing which items they stop and look at. Do they stop and look at an item just because its sharp? Nope. One can get that same experience of what people like by taking a look at which images get comments on PF, or which images get close to winning a prize in bigger contests. Its usually the picture that has a better story to tell, IMO.
08-19-2014, 12:00 PM   #821
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QuoteOriginally posted by thibs Quote
Yep but it doesn't mean those are the only measurements we should work with.
Nobody would review a car sticking only to the specs sheet. Otherwise, PDF download from the manufacturer's website is a review.

I agree..... I guess that's where this forum is so valuable. There are so many fantastic photographers on the forum and they show their work and tell which lens was used and discuss the results. I continue to learn from you all. Makes choosing a new lens much easier
08-20-2014, 07:02 AM   #822
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QuoteOriginally posted by northcoastgreg Quote
There's an old Japanese lens roadmap where the DA* 200 and DA* 300 lenses are listed as "DFA" glass.
well look at that there's a "DA 70-300" that got scrapped and probably the DA 55-300 replaced it.
08-20-2014, 07:32 PM   #823
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QuoteOriginally posted by philbaum Quote
Its usually the picture that has a better story to tell, IMO.
Yes, the better story and with sufficient technical excellence to not obscure or distort the telling of the tale.


Steve

---------- Post added 08-20-14 at 07:35 PM ----------

QuoteOriginally posted by Alizarine Quote
well look at that there's a "DA 70-300" that got scrapped and probably the DA 55-300 replaced it.
Except that the DA 55-300 has been around for a loooong time. At least it was a purchase option in 2007 when I bought my K10D.


Steve
08-20-2014, 09:38 PM   #824
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QuoteOriginally posted by stevebrot Quote
Except that the DA 55-300 has been around for a loooong time. At least it was a purchase option in 2007 when I bought my K10D.
That road road map is dated 2006 / 2007 so it is possible the 70-300 mentioned there was released as the 55-300. Certainly the 55-300 is not on it.

And it looks positively sparse. Perhaps those complaining in other threads that Pentax has few lenses should look at what was available in 2006. I'm not saying everything is rosey, but look at where we were and where we are. Quite a bit of progress.
08-20-2014, 09:46 PM   #825
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QuoteOriginally posted by jatrax Quote
That road road map is dated 2006 / 2007 so it is possible the 70-300 mentioned there was released as the 55-300. Certainly the 55-300 is not on it.

And it looks positively sparse. Perhaps those complaining in other threads that Pentax has few lenses should look at what was available in 2006. I'm not saying everything is rosey, but look at where we were and where we are. Quite a bit of progress.
Yes, things were sparse and it is entirely possible that the 55-300 was released along with the K10D and K100D. There were also a couple of lenses available then that are were discontinued a year or so later. It would be sort of interesting to do a full graphic of lenses available since the release of the *ist D.

Edit: I just took another look at the 2006/2007 "roadmap" and also the lens listings on Bojidar Dimitrov's Pentax K-Mount Page. I was mistaken regarding the 55-300. It did not debut until 2008, though I think it was early in the year. My office mate bought one to go with his K10D about that time. Several lenses listed for 2007 on the roadmap did not release until 2008 or 2009 including the DA 35/2.8 Limited, DA* 55/1.4, DA 17-70/4, and DA* 60-250/4. One thing that the chart did not show were the FA lenses that were still in production at the time.


Steve

Last edited by stevebrot; 08-20-2014 at 10:18 PM.
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