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05-21-2016, 09:10 AM   #16
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QuoteOriginally posted by HoustonBob Quote
The new sensor is capable of resolving about 110 Line Pairs/mm.
Somewhat less than a K-5? There is no reason to assign a handicap or special rating scale for a so-called film era lens based on the K-1 sensor any more than to do so for the K-3/K-3II.


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05-21-2016, 09:59 AM   #17
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QuoteOriginally posted by HoustonBob Quote
Take any 35mm color film you want put it in an MZS use the same lenses on a K-1 and the K-1 will blow the color film away - and it won't be close. I did an awful lot of color film photography 45 years ago - it isn't even close.
I also did an awful lot of color film photography 45 years ago and continue to do so. I also shoot the same lenses on my film cameras as on my K-3. Those lenses perform much better on the K-3 than with Ektar 100 and much better on Ektar 100 than with Kodachrome (any version). Strangely, this is true across the board even for my consumer-grade vintage lenses.

Is Ektar 100's ability to capture detail (different than resolution) equal to my K-3? No, I don't believe so, though it may be close to that of your K-1. This sort of discussion could go on and on. Kodak publishes the MTF data for their films and the Web is full of many comparison images. It is a rat hole and not pertinent. The issue is not how well film resolves, but how well lenses perform.

Going back to my first paragraph, evidence from actual use disputes the assertion that "designed for film" lenses intrinsically perform poorly with high resolution media. The Pentax-M 50/1.7 was tested in-camera to 100 lp/mm by Modern Photography in the early 1980s using available films. I see no reason why a good copy of the same model should not do at least as well on your K-1. They appear to on my K-3.

Edit: It would be interesting to see how many "digital design" lenses resolve to 100 lp/mm.


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Last edited by stevebrot; 05-21-2016 at 10:16 AM.
05-21-2016, 10:15 AM   #18
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QuoteOriginally posted by HoustonBob Quote
OK, I found a comparison. The film scan was 7191x4766 - very close to the resolution of a K-1.
QuoteOriginally posted by HoustonBob Quote
I have tried scanning Ektar 100 at 9600 dpi - with a scanner that can do that resolution honestly.
OK...I gotta ask. I know it is not pertinent to how well lenses do, but what scanner are you using? Even a Flextight is not able to do 9600 dpi and few folk are willing to devote space, expertise and money to owning a drum scanner.


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05-21-2016, 12:27 PM   #19
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QuoteOriginally posted by HoustonBob Quote
I would like to suggest a rating system for judging the resolution of old film lenses for use on the New K-1. The new sensor is capable of resolving about 110 Line Pairs/mm. The very best 35mm color film could resolve about 50 lp/mm. Old film lenses generally exceeded the resolution capability of 35mm color film by a small margin; say 55-65 lp/mm - since there was little point in having lenses sharper than that - as that sharpness couldn't be seen in photographs.
There are a lot of old Pentax prime film lenses which starts at 70lp/mm wide open and some of them in between f/5.6 and f/11 goes to 90-100lp/mm. Extreme example is FA 50mm f/2.8 macro which goes to 110lp/mm.
Here is a short (and not complete) list of those lenses:
PENTAX K 28mm f/3.5
PENTAX K 30mm f/2.8
PENTAX K 35mm f/3.5
PENTAX K 50mm f/1.2
PENTAX K 55mm f/1.8
PENTAX K 55mm f/2
PENTAX K 85mm f/1.8
PENTAX M 28mm f/2
PENTAX M 50mm f/1.7
PENTAX A 28mm f/2
PENTAX A 50mm f/1.2
PENTAX A 50mm f/1.7
PENTAX FA* 24mm f/2
PENTAX FA 35mm f/2
PENTAX FA 50mm f/1.4
PENTAX FA 50mm f/2.8 macro

05-21-2016, 06:08 PM   #20
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QuoteOriginally posted by stevebrot Quote
OK...I gotta ask. I know it is not pertinent to how well lenses do, but what scanner are you using? Even a Flextight is not able to do 9600 dpi and few folk are willing to devote space, expertise and money to owning a drum scanner.


Steve
I have a Canoscan 9000 F Mk ii - which is widely considered the equal of any film scanner generally available on the market - it has 9600 dpi optical resolution.

I will shut up about film and admit I am wrong if somebody will simply do what I did, Take two full frame 35mm shots of real world color scenes - like I did - one with your film and one with a K-1 and show me that a blown up section of the film resolves more detail than the same section of the K-1 shot does.

I have shot Velvia 50 - all I can say is good luck.

Let me explain how color film gets such high resolution numbers. The answer is that when they run those tests they don't use it as a color film - they take a picture of a black and white target. Now they have changed from being a color film - to essentially being a black and white film - which gives wildly inflated resolution numbers. But actual resolution on real world color scenes isn't even close to those inflated test numbers. The lp/mm ratings of color film only mean something when you are taking pictures of black and white test targets. It isn't exactly lying - it is more just advertising puffery.

Now I would like to clear up the confusion about which camera resolves more - the K3 or the K1. The K3 has smaller pixels and so some people think it resolves more detail because of those smaller pixels. While it does have smaller pixels the K3 does not resolve more detail in a picture than the K1. This is easily demonstrated with a thought experiment: Have the two cameras take a picture of the same scene with equivalent lenses - say a 50mm on the K3 and a 75mm on the K1. Now print 20" x 30" picture of the scene from the two files. The K3 picture will only have 24 million pixels in it while the K1 picture will have 36 million pixels. Because the picture has to be magnified more with the k3 the pixels on the printed picture wind up larger than the pixels on the K1 picture - the K1 will be able to resolve smaller objects in the picture than the K3. End result: the K1 is a higher resolution camera than a K3.
05-21-2016, 06:40 PM   #21
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Hold on. Why would you change the lens when this thread is about rating lenses?

Yes, when matching the FOV is the aim the K-1 has more resolution, you can simply compare the MP in this case.


Keeping the same lens the APSC crop of the K3 has more resolution than the APSC crop of the K-1 and thus is more taxing on the lens' resolution.
05-21-2016, 08:04 PM   #22
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QuoteOriginally posted by Topsy Quote
Hold on. Why would you change the lens when this thread is about rating lenses?

Yes, when matching the FOV is the aim the K-1 has more resolution, you can simply compare the MP in this case.


Keeping the same lens the APSC crop of the K3 has more resolution than the APSC crop of the K-1 and thus is more taxing on the lens' resolution.
Yes K3 is more taxing on the lens resolution but the K3 is not higher resolution. We both agree on that.

---------- Post added 05-21-16 at 10:09 PM ----------

QuoteOriginally posted by banep Quote
There are a lot of old Pentax prime film lenses which starts at 70lp/mm wide open and some of them in between f/5.6 and f/11 goes to 90-100lp/mm. Extreme example is FA 50mm f/2.8 macro which goes to 110lp/mm.
Here is a short (and not complete) list of those lenses:
PENTAX K 28mm f/3.5
PENTAX K 30mm f/2.8
PENTAX K 35mm f/3.5
PENTAX K 50mm f/1.2
PENTAX K 55mm f/1.8
PENTAX K 55mm f/2
PENTAX K 85mm f/1.8
PENTAX M 28mm f/2
PENTAX M 50mm f/1.7
PENTAX A 28mm f/2
PENTAX A 50mm f/1.2
PENTAX A 50mm f/1.7
PENTAX FA* 24mm f/2
PENTAX FA 35mm f/2
PENTAX FA 50mm f/1.4
PENTAX FA 50mm f/2.8 macro
Those are all excellent lenses which are going to do very well on the K1.

Last edited by HoustonBob; 05-21-2016 at 08:10 PM.
05-21-2016, 08:37 PM   #23
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QuoteOriginally posted by HoustonBob Quote
The K3 has smaller pixels and so some people think it resolves more detail because of those smaller pixels. While it does have smaller pixels the K3 does not resolve more detail in a picture than the K1.
Your opinion...

I used to be fairly good at thought experiments and did mine proactively before I posted my previous comments. Same lens (apples to apples) and same magnification (oranges to oranges). After all, we are talking about detail capture at the sensor and using that as the basis for assessing lenses, right? Adding additional variables introduces uncertainty in the results and playing the equivalence game is not needed here.

I would venture that a 50% K-1 lens would rate at about 45% as a K-3 lens using the methods in the original post.

In regards to the comparison shots between the K-1 and Ektar 100 scans...I don't believe the scan reflects my experience with that film, though I must confess to never having scanned to greater than 4000 dpi.


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05-21-2016, 08:51 PM   #24
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QuoteOriginally posted by stevebrot Quote
I would venture that a 50% K-1 lens would rate at about 45% as a K-3 lens using the methods in the original post.
I did the test with some K-3 images done with a few of my better film-era lenses and was not able to find a "wall" where greater detail was not revealed at greater magnification (up to 100%). The test images were of subjects with high detail and the lens was set to a moderate aperture. Even the Russian Zenitar Fisheye ramped all the way to 100%...go figure...


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05-21-2016, 09:12 PM   #25
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QuoteOriginally posted by stevebrot Quote
Your opinion...

I used to be fairly good at thought experiments and did mine proactively before I posted my previous comments. Same lens (apples to apples) and same magnification (oranges to oranges). After all, we are talking about detail capture at the sensor and using that as the basis for assessing lenses, right? Adding additional variables introduces uncertainty in the results and playing the equivalence game is not needed here.

I would venture that a 50% K-1 lens would rate at about 45% as a K-3 lens using the methods in the original post.

In regards to the comparison shots between the K-1 and Ektar 100 scans...I don't believe the scan reflects my experience with that film, though I must confess to never having scanned to greater than 4000 dpi.


Steve
I have to ask this question: "Why stop with a K3?" If you crop a K3 sensor to the size of a Pentax Q sensor the Q is much more demanding of lenses than the K3. Everything you have said argues more for using the Q than the K3.

This thread was about evaluating film lenses for use on the K1. It didn't have anything to do with the K3 or any other digital camera.
05-21-2016, 10:58 PM   #26
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Your method is flawed. The reliance on uncalibrated equipment with variable visual acuity observers using a method that asks them for subjective decisions...

Also your basic assumption is flawed. Film / color in particular / didn't dictate optical design limits. Optics may have only been measured that way, but they often outperformed film dramatically as we found out over time testing the lenses on modern digital cameras.
Your point about the q is actually on point. Using it to benchmark center resolution tells us a lot about how far in excess of film resolution we can get from some glass. Corner resolution on the k-1 may be more of a stress test due to it being in the corners that the lens performance suffers.

Why not just use standard lens testing methods?
05-22-2016, 12:03 AM   #27
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QuoteOriginally posted by HoustonBob Quote
I have a Canoscan 9000 F Mk ii - which is widely considered the equal of any film scanner generally available on the market - it has 9600 dpi optical resolution.

I will shut up about film and admit I am wrong if somebody will simply do what I did, Take two full frame 35mm shots of real world color scenes - like I did - one with your film and one with a K-1 and show me that a blown up section of the film resolves more detail than the same section of the K-1 shot does?
Well, if your comparison earlier in this thread is between the Pentax K-1 and a 35mm Ektar 100 shot scanned on a entry level consumer flatbed scanner like the Canoscan 9000 F Mkii, then I would conclude that your comparison is flawed. According to the German film scanner test site "www.filmscanner.info" the Canoscan can only produce a 1700ppi scan of 35mm film, which is the equivalent of about 4mp. You are hardly doing film any justice comparing the Pentax K-1 with a 35mm negative scanned on such a scanner.

Detailed test report flat bed scanner Canon CanoScan 9000F Mark II; evaluation of the image quality of the scanner

The best scanners for 35mm (Minolta Dimage Scan Elite 5400, Nikon 5000, Imacon, drum scanners) can produce scans that could capture much of the information held on a 35mm negative or slide, and yield scans around 24mp with a colour slide film like Provia 100F. Now a comparison between the very best fullframe DSLRs and a professionally scanned 35mm would make a relevant point of departure for an interesting comparison. But wait, there has already been published such comparisons. Here is one of the most interesting ones:

https://www.onlandscape.co.uk/2014/12/36-megapixels-vs-6x7-velvia/

Last edited by bjolester; 05-22-2016 at 02:12 AM.
05-22-2016, 01:14 AM   #28
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QuoteOriginally posted by HoustonBob Quote
I have a Canoscan 9000 F Mk ii - which is widely considered the equal of any film scanner generally available on the market - it has 9600 dpi optical resolution.
i use this scanner too. I do 13x19" prints from neg and from scanned neg with the CanoScan. To be clear, the optical print from the neg have a lot more details than the the scanned one. Especially if there is a crop.

I found with the CanoScann, that beyond 3600 dpi, the scan is always the same, just enlarged.
05-22-2016, 03:03 AM   #29
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QuoteOriginally posted by bjolester Quote
I would conclude that your comparison is flawed. According to the German film scanner test site "www.filmscanner.info" the Canoscan can only produce a 1700ppi scan of 35mm film, which is the equivalent of about 4mp. You are hardly doing film any justice comparing the Pentax K-1 with a 35mm negative scanned on such a scanner.
When the scan with whatever effective resolution already shows the film's grain, it won't be useful to increase the scanner resolution. What would you get from that? Sharper outlines of the individual silver halegonide crystals that make the film's grain?

The situation would be different if there were no visible grain on the scan. Then, and then only could we conclude that the scanner's effective resolution is insufficient.

But here? When a scanner with an effective resolution of 1700 ppi already shows the film's grain, that film can't have that mystical super-ultra-mega resolutions analogue addicts dream about.
05-22-2016, 03:25 AM   #30
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QuoteOriginally posted by funktionsfrei Quote
When the scan with whatever effective resolution already shows the film's grain, it won't be useful to increase the scanner resolution. What would you get from that? Sharper outlines of the individual silver halegonide crystals that make the film's grain?

The situation would be different if there were no visible grain on the scan. Then, and then only could we conclude that the scanner's effective resolution is insufficient.

But here? When a scanner with an effective resolution of 1700 ppi already shows the film's grain, that film can't have that mystical super-ultra-mega resolutions analogue addicts dream about.
No current flatbed scanner is able to scan with the necessary resolution to produce a scan from 35mm film where film grain is evident. One would need one of the absolete high end film scanners (Nikon, Minolta etc), Hasselblad Imacon, drum scanner, or indeed a "scan" with a high resolution DSLR like the Pentax K-1, to scan with the necessary resolution to end up with a scan that shows film grain. What you are seeing in the Canoscan scan is digital smearing/noise.

Last edited by bjolester; 05-22-2016 at 07:08 AM.
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