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08-10-2010, 07:24 AM   #151
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QuoteOriginally posted by Digitalis Quote
Takes A deep breath

from my testing the pentax K 50mm f/1.2 has a different resolution characteristic from the canon 50mm f/1.2 which I own and use from time to time. In my testing with a pentax LX on T-Max 100 at f/2.8 the SMCP 50mm f/1.2 has higher overall resolution in the periphery of the imaging field than the Pentax SMCP-FA 50mm f/1.4. The Canon 50mm f/1.2L is close to the SMCP 50mm f/1.2 @f/2.8 however the image quality at the edges of the frame are a bit softer in comparison to the SMCP 50mm f/1.2

The SMCP 50mm f/1.2 has extremely low Purple fringing*,however it does possess transverse chromatic aberration which is exacerbated at closer focusing distances, it is most apparent at the periphery of the imaging field. It is my personal opinion in regards to optical aberrations the Canon 50mm f/1.2 is an inferior performer when compared to the SMCP 50mm f/1.2

The DA*55mm has higher amounts of PF and CA than the SMCP 50mm f/1.2. The FA 50mm f/1.4 is an old design, but it is basically identical to most of the 50mm f/1.4 "me too" lenses. The DA*55mm f/1.4 uses a different optical formula in comparison to the SMCP 50mm f/1.2 and FA50mm f/1.4 lenses. And since the lenses are of a different focal length it becomes increasingly difficult to quantify and compare results.

In the case of the canon lens no, it really isn't worth it. because the Canon EF 50mm f/1.2L has a T stop of T=f/1.33- the SMCP 50mm f/1.2 has a T stop T=f/1.22(as I recall) so IMO it isn't even worth comparing the two lenses.

the colour and contrast doesn't just vanish, it's still there. what do you think PP,darkroom filters and variable contrast papers are for? Do you expect every image from your lenses to be perfect in colour and contrast? even without application of rudimentary PP? I have never seen a jeweller present a finished ring with an uncut diamond in its setting.

Well that would be a $15,000 mistake. but from my ownership of leica lenses and cameras i'm sure the 50mm f/0.95 ASPH can take more abuse than most lenses will ever be subject to. I use my noctilux 50mm f/1.0 without the ND filter. As Ansel Adams said "If your lens has bad vignetting, use it to frame your subject" those ND filters are for nitwits who obsess over achieving this ridiculous ideal of perfection. The tools we are using are imprecise, compare the shutter mechanism of a Nikon F5 to a swiss designed invar watch movement and the shutter from the F5 will look like a crude contrivance.

*I'm not entirely sure what causes PF, there are hypotheses some claiming it is UV light,some saying it is a sensor defect. I have another theory, but I need more hard data to come to any conclusions. All I know for certain lenses suffer from inordinate amounts of it; FA77LTD and DA 12-24mm f/4 are the worst culprits. Yet, some lenses appear to be remarkably free from it.
I know you're testing a film result against a modern MTF reading, which is why the issue is as speculative as counting angels dancing on the head of a pin.

When Photozone and other sites have gone back and tested legacy glass with high expectations, generally, the legacy glass has not performed well. I am not sure what you mean by "resolution characteristic". It either has the resolving accuracy or it does not. The only way to know is via MTF. Until then a T-Max film res count through a loupe is subjective. And the issue was not how they performed at 2.8, but at 2.0. The Canon 1.2 and 1.4 are equals at about 1.7 and they are modern lenses of comparative vintage. Again, until the testing benchmark is similar, I have doubts that the Pentax A 50/1.2 is superior to a more modern Canon offering. the Pentax has terrific bokeh. The resolution........let's see some real numbers. Prove me wrong. Someone send a good copy of the A 1.2 to Photozone with some pleading. It would be fascinating.

What also speaks volumes is that there has been no 1.2 Pentax released in well over 20 years, and that those from other companies are priced very, very high. You'd think that companies would push these out for the cachet and high margins, but they do not. Likely the reasons are optical quality issues in an age that values resolution and sharpness which they simply cannot deliver, made more obvious in digital negatives. These lenses would disappoint the market as much as excite it.

Yes, loss of contrast can be lost data if it never reaches the sensor through the Bayer filter. I don't expect cameras and lenses to be perfect (Lecia does: Leica Camera AG - Photography - M9). I do know that the pursuit of ultra-fast glass involves irrecoverable compromises. You get amazing bokeh and a 3D pop in the centre of the frame. Everything else is compromised...by design.

With PP and Photoshop in the equation, the economics of these lenses doesn't make much sense. It is far more cost-effective for the photographer put those resources into software manipulation. Yes, there is data integrity and authenticity arguments, but at these apertures, the competition is Photoshop! Or a Hasselblad: flores | Flickr - Photo Sharing!

I can't beat this comment from LL regarding the ultra-wide aperture lenses (404 ERROR PAGE

"... I question how long or how often a photographer can use it before he begins repeating himself visually. Rather, a lens like this is a creative tool thatĺs fun to reach for when you want to do more creative or experimental work."

Most newbies here look for the fast glass solution for a host of issues, such as capturing shots of running kids indoors. The same can be said for the nightclub shots, handheld shots, etc. Too fast glass is not a photographic solution to the majority of real world solutions. Noise-free high ISO sensors, better flash, and PP are.

08-10-2010, 07:35 AM   #152
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QuoteOriginally posted by Aristophanes Quote
I know you're testing a film result against a modern MTF reading, which is why the issue is as speculative as counting angels dancing on the head of a pin.

Too fast glass is not a photographic solution to the majority of real world solutions. Noise-free high ISO sensors, better flash, and PP are.
I agree with your last point, there are many situations where I have thought to myself: I could have all the lens speed in the world, but with this light, i'm still going to get crap.

I don't think software is ever going to replace great optics. Sure, it can get close to producing those effects but lenses like the noctilux in particular possess a "soul" a unique way of rendering a scene that is utterly unmistakable this is also referred to as a lens' "signature". The Leica 50mm f/1.0 Noctilux has possibly the worst coma I have ever seen in a mass produced lens, the vignetting isn't that great either. And the "glow" the noctilux produces is nothing more than uncorrected spherical aberrations. However, these three attributes are what make the noctilux the Legend that it is. So to a large extent aesthetics will rule over whether one lens is sharper than another, or which pinhead has the most dancing angels....

Last edited by Digitalis; 08-10-2010 at 07:42 AM.
08-10-2010, 08:26 AM   #153
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QuoteOriginally posted by Aristophanes Quote
I know you're testing a film result against a modern MTF reading, which is why the issue is as speculative as counting angels dancing on the head of a pin.
Not exactly a serious comment.

But I know you'll all love it

Below is a tack-sharp crop from the DA 70 Ltd. lens of a test chart, magnified to 400% (so you see the pixels). It's really a very high level of magnification, the circles' square is 1cm on an A2 test chart which fills the frame. This is as good as it gets with a 15MP camera. And photozone.de uses a Pentax 10MP camera

The left inset is an inset shot with the same lens and again with the A2 test chart filling the frame (ok, I admit, the frame is slightly larger, i.e., full frame ) But now shot on film (ok, I admit, high resolution film). The image was taken with a professional microscope because film scanner resolutions are too low to resolve this much of detail.

Images taken from an article under preparation

The extra level of detail possible with the DA70 Ltd. amazes me.
I think "counting angels dancing on the head of a pin" is feasible with film

A 15MP sensor (or resolution tests done with it) don't do it justice. This is why all resolution charts in the internet (in the post analog MTF era) must be ignored when it comes to the excellent lens category. I always only look at the aperture where the MTFs peak, not the absolute resolution figures when high.

Enjoy

Last edited by falconeye; 06-23-2012 at 03:08 AM.
08-10-2010, 08:41 AM   #154
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QuoteOriginally posted by falconeye Quote
Not exactly a serious comment.

But I know you'll all love it

Enjoy
Didn't you mention God in another thread? Is the DA70 designed by the Almighty so we might see said angels?

These tack sharp test charts are impacting theology, poetry, and photography!

I don't know what to look for anymore. If I go back to film, I guess I'll have found religion.

08-10-2010, 08:45 AM   #155
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QuoteOriginally posted by falconeye Quote
The extra level of detail possible with the DA70 Ltd. amazes me.
Now you made me want a 40mp sensor for my DA70 :-)
(and I thought the fact that it gives me moire on the K10d all the time was proof that it's sharp)
08-10-2010, 08:56 AM   #156
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QuoteOriginally posted by gazonk Quote
Now you made me want a 40mp sensor for my DA70 :-)
40MP?

The inset to the left, if 100%, would correspond to 200MP ... However, might not be tack-sharp on digital anymore, so, I would be fine with 100MP
08-10-2010, 09:02 AM   #157
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QuoteOriginally posted by falconeye Quote
40MP?

The inset to the left, if 100%, would correspond to 200MP ... However, might not be tack-sharp on digital anymore, so, I would be fine with 100MP
I'm just worried that a 100mp APS-C camera might be slightly noisy even at ISO 25
08-10-2010, 09:06 AM   #158
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QuoteOriginally posted by falconeye Quote
40MP?

The inset to the left, if 100%, would correspond to 200MP ...
I'm currious with which film you made this picture, and of course, given the circle of confusion, how you achieved focus and made sure that the film was properly flatten out.

08-10-2010, 09:08 AM   #159
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QuoteOriginally posted by gazonk Quote
I'm just worried that a 100mp APS-C camera might be slightly noisy even at ISO 25
Noisier than the film snippet I've shown?
Seriously though, a 100MP FF sensor would have 3Ám pitch, still twice the surface per pixel as in an LX3. And in low light, you can downsample to 10MP if you like Which bins 10 Pixels into 1
08-10-2010, 09:13 AM   #160
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QuoteOriginally posted by falconeye Quote
Noisier than the film snippet I've shown?
Seriously though, a 100MP FF sensor would have 3Ám pitch, still twice the surface per pixel as in an LX3.
And it would allow to get rid of antialiasing filter, to ge a more complex color matrix than bayer filter (better color accuracy)

Sure the raw files would be massive, but 20Mpx or so intermediate files could be produced with pixel merging like Canon already does.

I'm quite sure it will be done some time in the future, it wait for the progress in sensor tech.
08-10-2010, 12:10 PM   #161
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QuoteOriginally posted by falconeye Quote
Noisier than the film snippet I've shown?
Seriously though, a 100MP FF sensor would have 3Ám pitch, still twice the surface per pixel as in an LX3. And in low light, you can downsample to 10MP if you like Which bins 10 Pixels into 1
Ah, you're talking about a 100 MP FF sensor. That's actually pretty close in pixel density to the 40 MP APS-C sensor I talked about. I thought we were discussing the optimal back end for the DA70
08-10-2010, 04:22 PM   #162
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QuoteOriginally posted by gazonk Quote
Ah, you're talking about a 100 MP FF sensor. That's actually pretty close in pixel density to the 40 MP APS-C sensor I talked about. I thought we were discussing the optimal back end for the DA70
Actually, I rather was confused. The film snippet was from a full frame done with DA70 and the corners were softer but not unusably so. So, I imagined the DA70 mounted to a full frame digital which isn't technically correct.

Anyway, we're having a fun talk and factors two don't matter much, hey?
Lenses for 100MP digital full frame cameras seem to be feasible though.
08-10-2010, 08:07 PM   #163
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QuoteOriginally posted by ghelary Quote
Both are half a stop difference. Canon 85/1.2 is commonly compared with Zeiss 85/1.4.

The "special thing", with 1.2 is that it's so rare compared to the more common 1.4. The 1.2 lenses are specially studied for bokeh, not for DOF (focal length makes more difference) or low light performance (half a stop is not that much)
A half a stop of light from 1.4 to 1.2 is more than a half a stop of light from f 1.7 to f1.4. Its not a linear relationship working from 32 to 1.

Last edited by Blue; 08-10-2010 at 08:14 PM.
08-10-2010, 09:15 PM   #164
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QuoteOriginally posted by Aristophanes Quote
I don't know what to look for anymore. If I go back to film, I guess I'll have found religion.
Many believe that, yes.
08-11-2010, 03:07 AM   #165
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"Canon 85/1.2 is commonly compared with Zeiss 85/1.4"

These days Zeiss lenses are really cosina products in drag. And the Canon EF 85mm f/1.2L is a sub standard lens in comparison to the Pentax FA*85mm f/1.4

" ..not for DOF (focal length makes more difference).."

you have much to learn ghelary.


"..or low light performance (half a stop is not that much).."

it's more than you think.
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