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04-14-2011, 10:58 AM   #76
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QuoteOriginally posted by yeatzee Quote


Not all of us want an APSC equivalent like the DA*55mm..... some of us actually want an 85mm F/1.4
Totally. May I add that multiplying by 1.5/1.4 to get an equivalent just does not make sense. A 50mm or 55mm will never give me the same perspective (the whole FoV, not just a crop) I get from an 85mm [Off topic, but, instead of the 35mm Equiv. in the EXIF, I'd like to see the microfocus adjustment value captured. Imagine how much that's going to help when you are testing your lens]


QuoteOriginally posted by yeatzee Quote


SIGMA,
Thank you for stepping up and doing what had to be done! These old used pentax lens prices are ridiculous to say the least nowadays. BUT, and this is a big but, WTF is with making us pay significantly more for a lens to be released in K mount that is already on other mounts with useless image stabilization?
I second this and a lot of other statements in this thread. And btw, just sharpness is not all in a lens. There are other qualities too. Like the bokeh, MF/AF, AF speed, etc. People have different needs and pockets. And yes, the biggest would be availability.

04-14-2011, 11:24 AM   #77
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QuoteOriginally posted by dasuhu Quote
I know resolution is dependent on factors such as subject distance, spherical aberrations, coma, and contrast, but I did not know it was dependent significantly on focal length (independent of the aperture gains). Fascinating

Do you know of any place to read up on this, with scientific jargon included? As a student in science, the technical sides of optics fascinate me almost as much as the artistic photographs making sides of things.
I read it in russian so I doubt it can be translated properly. But I can do some basic explanation why it happens. The resolution empiric formula is definitely right for the only glass. But we know each lens is an ordered set of glasses. The light reach the first glass at first, the second at second, etc. And each following glass receives exactly the same light (image ) the previous one passed. As we know, the resolution is ability to split two close spots. And if the previous glass added more magnification, it's easier for the current one to split them, since those spots became a little more distant. Simple!
04-14-2011, 11:57 PM   #78
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Sigma seems to have narrow sharp and soft at f/1.4..
04-15-2011, 07:26 AM   #79
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QuoteOriginally posted by vegabraveian Quote
Sigma seems to have narrow sharp and soft at f/1.4..
Goodbye.

04-15-2011, 08:38 AM   #80
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QuoteOriginally posted by outsider Quote
Goodbye.
You say goodbye and I say hello. Hello hello
04-15-2011, 08:48 AM   #81
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I would take the Sigma 85mm over the FA 77mm for a couple of reasons, and over the FA* 85mm for a couple of other reasons.

The FA77 is a great lens stopped down, but its bokeh is a little harsh. In even light and with a controlled background it generates excellent images and has great color.

The Sigma wins on price/IQ/AF/bokeh/speed. I'm sure the used FA* 85mm will come down in price now that there is another option in production. FA* 85 is an excellent lens, but it is not worth the price to anyone but a Pentax gear collector.

Sigma is rumored to be releasing a 135mm f/2 which should also be a really good lens and give Pentax users a ~200mm prime.

Since I tend to favor longer glass I prefer the FF glass on APS-C bodies. I really like 28-75mm on an APS-C body.
04-15-2011, 08:58 AM   #82
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QuoteOriginally posted by Winder Quote
Sigma is rumored to be releasing a 135mm f/2 which should also be a really good lens and give Pentax users a ~200mm prime.
I'm not sure if this rumor would become a reality, but if it does, that would be great. for now, the upcoming Sigma 150 macro would suffice.
04-15-2011, 09:09 AM   #83
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QuoteOriginally posted by Pentaxor Quote
I'm not sure if this rumor would become a reality, but if it does, that would be great. for now, the upcoming Sigma 150 macro would suffice.
The Sigma 150 Macro is one lens that really piques my interest. I'm thinking of pre-ordering that one, although it might be a while till we actually see it in k mount, given the to-be-expected delays.

04-15-2011, 09:35 AM   #84
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QuoteOriginally posted by vegabraveian Quote
Sigma seems to have narrow sharp and soft at f/1.4..
What???! I would have agreed if you said it has fringing wide open. But not sharp? I politely disagree. Please see the pictures on page 2 of this thread.

Or maybe you are talking in comparison terms. In which case, compared to what? Do you have pictures that explains what you believe? Please share.
04-15-2011, 10:14 AM   #85
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QuoteOriginally posted by icypepsi Quote
Totally. May I add that multiplying by 1.5/1.4 to get an equivalent just does not make sense. A 50mm or 55mm will never give me the same perspective (the whole FoV, not just a crop) I get from an 85mm [Off topic, but, instead of the 35mm Equiv. in the EXIF, I'd like to see the microfocus adjustment value captured. Imagine how much that's going to help when you are testing your lens]
This is easy to demonstrate, too. The 30-35mm is the "approximate normal" for the APS/C sensors according to the 1.4/1.5 "crop factor"; but try this: Put a 35mm lens on your Pentax, hold the camera vertically, and open both eyes. Now do the same thing with a 50mm on the camera.
04-15-2011, 10:30 AM   #86
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QuoteQuote:
A 50mm or 55mm will never give me the same perspective
Don't be an idiot. They shows exactly the same perspective as 50λ or 55λ on 35mm film where λ is an APS-C crop factor.
04-15-2011, 10:44 AM   #87
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QuoteOriginally posted by Emacs Quote
Don't be an idiot. They shows exactly the same perspective as 50λ or 55λ on 35mm film where λ is an APS-C crop factor.
Someone missed out on a session or two of "How to win friends and influence people." Really, dude, there are many brands that are just as tasty without all the caffeine.
04-15-2011, 10:54 AM   #88
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QuoteOriginally posted by jstevewhite Quote
This is easy to demonstrate, too. The 30-35mm is the "approximate normal" for the APS/C sensors according to the 1.4/1.5 "crop factor"; but try this: Put a 35mm lens on your Pentax, hold the camera vertically, and open both eyes. Now do the same thing with a 50mm on the camera.
I think what he meant was the perspective distance between subject and background, not just necessarily FOV equivalence with another lens. aside from that, we also have to look at the perspective that certain focal lengths show regardless of sensor size. in short, FOV is the least of one's worry here. if one was looking for FOV necessity, they are looking at the wrong lens focal length.
04-15-2011, 11:02 AM   #89
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QuoteOriginally posted by jstevewhite Quote
Someone missed out on a session or two of "How to win friends and influence people." Really, dude, there are many brands that are just as tasty without all the caffeine.
Oh, ehmmm…
I wrote it with a smile (
04-15-2011, 11:08 AM   #90
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QuoteOriginally posted by jstevewhite Quote
Someone missed out on a session or two of "How to win friends and influence people." Really, dude, there are many brands that are just as tasty without all the caffeine.
well said. on the otherhand, maybe he needs to have one of these >>>
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