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04-13-2011, 11:08 AM   #61
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QuoteOriginally posted by Pentaxor Quote
I like the FA77, but I won't draw to that conclusion yet with only a few limited samples coming from the Sigma on a Pentax body.
I guess I'm right. We are living in the days of overcorrected lenses cause they want "sharpness from wide open". But it implies degradation in other characteristics since even FF sensor is just too small for optics to give sharp enough images (not even mention APS-C ). Todays optics are boring as hell, and I don't see this sigma is an exception.

04-13-2011, 11:49 AM - 1 Like   #62
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QuoteOriginally posted by Emacs Quote
But it implies degradation in other characteristics since even FF sensor is just too small for optics to give sharp enough images (not even mention APS-C ).
I wasn't exactly able to grasp what you meant by this statement. what degradation would sensor size cause to the image using a particular lens?

QuoteQuote:
Todays optics are boring as hell, and I don't see this sigma is an exception.
and what if Pentax release a new 85mm? would you consider it as boring because it is today's optics? the thing is, that Sigma stepped up to a photographers' needs where Pentax failed to do so. since when did Pentax came out with a new 85mm? the obvious answer is NADA. of course, others would argue that Pentax has a 77mm, but it is still not an 85mm, nor any faster than f1.8. or 77mm focal length is better suited for an APS-C rather than an 85mm, then why do people own a Samyang 85, FA*85, M85, etc... if that were true?

actually it's unfair to say that Sigma is no good because it is over-corrected. honestly, I can't even see how the term even fits the Sigma. is it because it is sharp wide open? heck, the FA77 is sharp wide open as well, same as the FA* 85. so I don't see the point on picking on it's sharpness at wide open as if it's some kind of a disease. I bet if it were soft at wide open, we can expect a more profound complaint that is underperforming which would had made more sense as a complaint.

the truth is, Sigma got a winner here (especially at CaniKon). although it may not please a few Pentax Users yet due it being released just only about a month, so it's just a matter of waiting game.
04-13-2011, 01:40 PM   #63
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QuoteOriginally posted by Pentaxor Quote
I wasn't exactly able to grasp what you meant by this statement. what degradation would sensor size cause to the image using a particular lens?



and what if Pentax release a new 85mm? would you consider it as boring because it is today's optics? the thing is, that Sigma stepped up to a photographers' needs where Pentax failed to do so. since when did Pentax came out with a new 85mm? the obvious answer is NADA. of course, others would argue that Pentax has a 77mm, but it is still not an 85mm, nor any faster than f1.8. or 77mm focal length is better suited for an APS-C rather than an 85mm, then why do people own a Samyang 85, FA*85, M85, etc... if that were true?

actually it's unfair to say that Sigma is no good because it is over-corrected. honestly, I can't even see how the term even fits the Sigma. is it because it is sharp wide open? heck, the FA77 is sharp wide open as well, same as the FA* 85. so I don't see the point on picking on it's sharpness at wide open as if it's some kind of a disease. I bet if it were soft at wide open, we can expect a more profound complaint that is underperforming which would had made more sense as a complaint.

the truth is, Sigma got a winner here (especially at CaniKon). although it may not please a few Pentax Users yet due it being released just only about a month, so it's just a matter of waiting game.
I'll tell you what's a winner. This statement is a winner. Very Good, solid points. With all the lenses coming out of the woodwork from several different manufacturers, it does make you kind of wonder what's going on. 77 1.8mm, 43mm 1.9, 40mm 2.8 or whatever. Where's the 85 1.4? What are they thinking behind closed doors sitting at those expensive mohogany tables, drinking fine coffee/sake. If anyone finds todays optics "boring", they just havent found the right lens yet. Take some time, do some research and fork out the cash and you'll find your keepsake.
04-13-2011, 03:32 PM   #64
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QuoteOriginally posted by Emacs Quote
Simple physics, I really tired to explain it to ignoramuses, but repeat: 85mm at pentax APS-C ≈ 127.5mm of effective focal range. It means it gives exactly the same picture as 127.5 would give at film/full frame sensor. But the real 127.5mm lens has 1.5 times larger magnification factor so it's 1.5 times easier for this lens to resolve details. The difference between 85mm on APS-C and 127.5mm of FF decreases when stopping down the aperture, but portrait lenses tend to be used at quite wide ones.
Isn't resolution dependent on aperture not focal length? Given a 85mm and 127.5mm lenses at the same f-stop (e.g. f/1.4), the latter lens should have higher resolution because of its larger effective aperture. Stopping down decreases theoretical resolving power, but can help things if doing so sharpens up the image (i.e. big aperture means nothing if the image quality is poor/soft).

04-13-2011, 04:14 PM   #65
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QuoteOriginally posted by Emacs Quote
Simple physics, I really tired to explain it to ignoramuses, but repeat: 85mm at pentax APS-C ≈ 127.5mm of effective focal range. It means it gives exactly the same picture as 127.5 would give at film/full frame sensor. But the real 127.5mm lens has 1.5 times larger magnification factor so it's 1.5 times easier for this lens to resolve details. The difference between 85mm on APS-C and 127.5mm of FF decreases when stopping down the aperture, but portrait lenses tend to be used at quite wide ones.
wow, you just really have to take a jab on such a civilized inquiry, dont you? forgive me for asking since I'm not as highly intelligent or informed as you are mister.

btw, we are talking about a certain particular lens (85mm) performance being used on APS-C and FF camera. so when did a 127mm lens or 135mm or whatever got involved in this?

you are probably talking about crop factor value and equivalence but not resolution of one particular lens on either system, so I'm going to ask you this question before we drift away further, does the center resolution of a particular 85mm lens on a FF camera differ from that of the same 85mm lens on an APS-C camera?

Last edited by Pentaxor; 04-13-2011 at 09:09 PM.
04-13-2011, 04:20 PM   #66
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QuoteOriginally posted by Emacs Quote
They don't need 85 f1.4 for APS-C. They have 55 f1.4 already.
just as I expected. so what's the need for the 77mm on an APS-C if there is a 55mm?

QuoteQuote:
And I'm not one who's ready to spent hours on softening images while 77Ltd make pictures just right.
it must be really difficult to learn a simple click and drag operation on the clarity slider button. even a young boy could do and learn that in a few seconds. maybe your previous comment applied to you more.

Last edited by Pentaxor; 04-13-2011 at 09:01 PM.
04-13-2011, 04:33 PM   #67
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QuoteOriginally posted by Emacs Quote
They don't need 85 f1.4 for APS-C. They have 55 f1.4 already.

In that case, I want a NEW ~135mm equivalent F/1.4 lens

I do not care for a 85mm F/1.4 equivalent (DA*55), I like the extra "reach" I get with APSC


(I'd also like a 200mm equivalent F/2 Pentax! That is a lens I truly lust after in Nikon mount )



edit: NO I am not talking about an actual 200mm F/2 or 135mm F/1.4, though such lenses would be quite neat!
04-13-2011, 04:38 PM   #68
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QuoteOriginally posted by yeatzee Quote
In that case, I want a NEW ~135mm equivalent F/1.4 lens

I do not care for a 85mm F/1.4 equivalent (DA*55), I like the extra "reach" I get with APSC


(I'd also like a 200mm equivalent F/2 Pentax! That is a lens I truly lust after in Nikon mount )



edit: NO I am not talking about an actual 200mm F/2 or 135mm F/1.4, though such lenses would be quite neat!

no, you don't understand. Pentax users don't need those for APS-C. only Canon and Nikon Users can have those focal lengths and speed for their DX and EF-S compatible cameras.

04-13-2011, 05:07 PM   #69
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QuoteOriginally posted by Pentaxor Quote
no, you don't understand. Pentax users don't need those for APS-C. only Canon and Nikon Users can have those focal lengths and speed for their DX and EF-S compatible cameras.




Id like to take this opportunity and also point out that not everybody thinks of a lens's focal length in regards to film/FF

Im 17, so I started photography with a DSLR. When I think of 85mm I think of what I see with my M 85mm F/2 on my K-7 not what I see with my tak. 55mm on my K-7

PENTAX,
I would love a longer portrait lens in true legendary Pentax fashion More specifically, I want a Pentax DA 135mm F/2 with AF as fast as the F 135mm F/2.8 but slightly sharper wideopen and with fantastic bokeh I'd also like a re-issue of some of the lenses that made pentax great, like the FA* 85mm F/1.4 Not all of us want an APSC equivalent like the DA*55mm..... some of us actually want an 85mm F/1.4

Sincerely,
an insignificant teenage pentax shooter

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?

Sincerely,
An insignificant teenage pentax shooter
04-14-2011, 02:51 AM   #70
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QuoteOriginally posted by dasuhu Quote
Isn't resolution dependent on aperture not focal length? Given a 85mm and 127.5mm lenses at the same f-stop (e.g. f/1.4), the latter lens should have higher resolution because of its larger effective aperture. Stopping down decreases theoretical resolving power, but can help things if doing so sharpens up the image (i.e. big aperture means nothing if the image quality is poor/soft).
It's true for some really high-end optics used in telescopes with their huge lenses. Photo optics is another case, their schemes prevent to achieve diffraction limit and thus they depend on the focal range very much. BTW, they are not even about reaching the limit, photography has slighltly different priorities.
04-14-2011, 03:00 AM   #71
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QuoteOriginally posted by Pentaxor Quote
just as I expected. so what's the need for the 77mm on an APS-C if there is a 55mm?
Headshoot lens. No more.
QuoteQuote:
it must be really difficult to learn a simple click and drag operation on the clarity slider button. even a young boy could do and learn that in a few seconds. maybe your previous comment applied to you more.
Mindless PP usually decreases picture quality. BTW I don't think $1200 lens images should be needed in obligatory PP. At least, my $900 77Ltd lets me only to perform basic tasks like correcting the exposure.
04-14-2011, 07:52 AM   #72
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QuoteOriginally posted by Emacs Quote
It's true for some really high-end optics used in telescopes with their huge lenses. Photo optics is another case, their schemes prevent to achieve diffraction limit and thus they depend on the focal range very much. BTW, they are not even about reaching the limit, photography has slighltly different priorities.
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.
04-14-2011, 08:51 AM   #73
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QuoteOriginally posted by Emacs Quote
Headshoot lens. No more.
and I cant do that with a 50/55mm lens ? not to mention a 100mm or 135mm ?

QuoteQuote:
Mindless PP usually decreases picture quality.
you are right about this. any image will look like crap if the person is utterly mindless. same with someone with a fantastic lens that doesn't know how to use it. if you know and you can learn how to use a lens properly, how does that stop you from post-processing? softening an image is not even rocket science and I wonder why would it take a common individual to spend hours doing so? it doesn't take a genius to learn how to turn on a tv switch.

Last edited by Pentaxor; 04-14-2011 at 10:31 AM.
04-14-2011, 09:35 AM   #74
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QuoteOriginally posted by DogLover Quote
I agree, looks pretty darned good! Dammit. That makes 2 thousand-dollar lenses that I know I want.
It's words like these that make me proud to be a J-9 user

Whatever the case, the lens looks amazingly sharp!
Not sure it has that "portrait quality" type of look to it, but there's no question about its capacity for amazingly sharp portrait. Definitely a candidate for studio work.
04-14-2011, 10:46 AM   #75
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QuoteOriginally posted by JohnBee Quote
It's words like these that make me proud to be a J-9 user

Whatever the case, the lens looks amazingly sharp!
Not sure it has that "portrait quality" type of look to it, but there's no question about its capacity for amazingly sharp portrait. Definitely a candidate for studio work.
Yeah, I've actually changed my mind (for now). I'm going to hold off on the 85 until I'm really convinced that I need it, and hopefully that day will never come! I'm just too satisfied with what I've been getting out of the 77 to feel lacking in this area.
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