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06-03-2021, 05:20 AM - 2 Likes   #16
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QuoteOriginally posted by Jeff Quote
I had been saving patiently for the DFA* 85mm 1.4 but it's just too heavy - half a pound or 250g heavier than the 50 DFA* which I own, and that in itself is a big beast. But I'm happy to go with my decision to get the 77 (and the 31) for not as big an outlay as the 85 would be...
I'm constantly reminded of how small the 77 is. Latest epiphany : I put it side by side with Sony's recently released 28-60 F4-F5.6 retractable zoom (a slow FF zoom, regarded as an amazing feat of engineering because it's so small). The F1.8 Limited is almost exactly the same size. That's for a lens 2.5 stops faster with no retractable elements!

QuoteOriginally posted by stevebrot Quote
As bdery noted above, the improvements will be what might be expected from what is expected to be an upgrade in coating. That said, the "ghostless" ("smc" is just the label on the lens) coatings on the non-HD FA Limiteds is nothing to sniff at.
Indeed the older SMC coatings were pretty good. The HD are clearly better, still.

QuoteOriginally posted by stevebrot Quote
PF is a sensor artifact that is related to, but not the same as longitudinal CA (LoCA).* Many fast high performance primes have residual LoCA and most (all) of those will fringe on digital if given a chance. Unless Ricoh/Pentax changed the optical designs, one would not expect a change in PF behavior.
QuoteOriginally posted by stevebrot Quote
PF (malignant purple/blue fringing) is something that does not present with film captures, even when the lens is severely provoked (slightly misfocused, overexposed, electronic flash on crumpled foil). Yes, I have tried.
Indeed, film isn't sensitive to UV the same way that digital sensors are.

QuoteOriginally posted by ehrwien Quote
Do lenses that produce more LoCa also produce worse PF? What is the relation between the two kinds?
I'd say that, in general, yes, but it's far from a hard rule. That's a case by case evaluation. PF is, in simple terms, caused by lenses not optimized for CA in the UV range of the light spectrum. So lenses which are poorly compensated in the visible (causing CA) are likely to be poorly compensated in the UV. But that's not a hard rule. You could tune your lens properly in the visible, but give up on UV, because this is the film era and who cares about UV, right? It could end up with a lens showing strong PF but low CA.

06-03-2021, 09:36 AM   #17
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QuoteOriginally posted by bdery Quote
Indeed, film isn't sensitive to UV the same way that digital sensors are.
I am familiar with the UV hypothesis and won't disagree. I have not been actively following the thinking of PF the last couple of years, but do know that current generation sensors seem to be much less prone. The CCD on my K10D would throw some amazing PF under some circumstances!

In regards to PF on film, it may depend on the film. It is common practice to use a UV filter to minimize haze from atmospheric scattering when shooting both color negative and positive films. (The yellow layer of Kodak Ektar 100 is quite sensitive at 400 and somewhat less at 380nm.) On the B&W side of things, Fuji Acros 100 (both original and type-II) films are famously "orthopancromatic" meaning extended blue into near-UV/UV sensitivity. (The original Acros formulation had the same sensitivity at 380nm as at 550nm.)

I have a cache of the original Acros 100 as well as a supply of Ektar 100 and the next time I am shooting either, I should do a few frames with the FA 77/1.8 so see if I can provoke PF. (My original try was with Kodak Gold 200.)


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06-03-2021, 11:30 AM   #18
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QuoteOriginally posted by stevebrot Quote
current generation sensors seem to be much less prone.
Yep, UV filtering has been improved in recent cameras. The sensor itself has physical properties and different sensor materials will yield different absorption spectra. For instance, working in the near infrared, you need to use a Indium Galium Arsenide (InGaAs) whereas for visible light you want a Silicon sensor. In-between you use a Germanium sensor.



Si sensors reach into the UV, that's a property of the material. You need to filter what you don't want.

QuoteOriginally posted by stevebrot Quote
In regards to PF on film, it may depend on the film.
Same basic discussion, most film was intended to be unable to absorb UV, but some weren't made that way.
06-11-2021, 11:29 AM - 1 Like   #19
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Bernard's review has been posted.
HD vs. SMC Pentax FA Limited Lenses Review - Introduction | PentaxForums.com Reviews

06-12-2021, 02:28 PM   #20
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QuoteOriginally posted by Tesla Quote
Thanks - I read the review and am glad I went for the SMC versions - I saved a lot of money and it seems that although the HD versions are good, the differences are not pronounced enough to make me regret my decisions. I picked up an 'as new' 77 and a new 31 for the cost of a new 31 HD version.

It was however great to read Bernard's review - these lenses really are special.
06-15-2021, 05:40 AM   #21
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QuoteOriginally posted by bdery Quote
Yep, UV filtering has been improved in recent cameras. The sensor itself has physical properties and different sensor materials will yield different absorption spectra. For instance, working in the near infrared, you need to use a Indium Galium Arsenide (InGaAs) whereas for visible light you want a Silicon sensor. In-between you use a Germanium sensor.

Si sensors reach into the UV, that's a property of the material. You need to filter what you don't want.

Same basic discussion, most film was intended to be unable to absorb UV, but some weren't made that way.
Interesting information this. I'm waiting to explore the UV capacities of my full spectrum converted K-3 II, but for now I'm focusing on IR instead. Filters that only let UV pass are expensive... And I gather there's no telling whether my lenses will let through a lot of UV either. I was lead to understand that the less coating the better, i.e. the cheaper glass being preferred for UV photography. Would the SMC vs HD coating make a difference for the limiteds in this respect as well, or would it be a very minor difference?
06-15-2021, 02:15 PM   #22
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QuoteOriginally posted by Ishpuini Quote
Interesting information this. I'm waiting to explore the UV capacities of my full spectrum converted K-3 II, but for now I'm focusing on IR instead. Filters that only let UV pass are expensive... And I gather there's no telling whether my lenses will let through a lot of UV either. I was lead to understand that the less coating the better, i.e. the cheaper glass being preferred for UV photography. Would the SMC vs HD coating make a difference for the limiteds in this respect as well, or would it be a very minor difference?
Or just win a large lottery and go looking for one of the quartz-takumars designed for UV photography

06-15-2021, 11:56 PM   #23
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QuoteOriginally posted by mlt Quote
Or just win a large lottery and go looking for one of the quartz-takumars designed for UV photography
Didn't know about these. If I have to save up for one of these, I'll have to skip too many others, so I'll just continue with IR instead of UV...
06-16-2021, 05:15 AM - 1 Like   #24
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QuoteOriginally posted by Ishpuini Quote
I was lead to understand that the less coating the better, i.e. the cheaper glass being preferred for UV photography. Would the SMC vs HD coating make a difference for the limiteds in this respect as well, or would it be a very minor difference?
If coatings are well-made, they will be band-pass, so they will in all likelihood cut some or most of the UV. HD, being designed for digital, would logically be designed that way (that's a safe guess, but a guess). No coatings means the lens won't have any chance of having a band-pass cutting the UV, but the choices of glass types will influence this also.
06-17-2021, 11:36 AM   #25
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The best thing about the HD versions of the Limiteds is that Pentax are still making them. Considering the difficulty of prising a Limited from its owners grasp, it's a consolation to those who still aspire to owning them that the seconhand market is not the only source.
06-17-2021, 11:51 AM   #26
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I havent seen any evidence to convince me of the need to upgrade my 43 to HD.....though as that is the only FA Ltd I have, Id be more than happy to take possession of an HD 31 or 77 in the current raffle. I agree that being upgraded, even slightly, is important simply as a way of keeping them in-production. The 43 is my favourite lens so I'm happy with it sticking around
06-20-2021, 06:04 AM   #27
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QuoteOriginally posted by bdery Quote
If coatings are well-made, they will be band-pass, so they will in all likelihood cut some or most of the UV. HD, being designed for digital, would logically be designed that way (that's a safe guess, but a guess). No coatings means the lens won't have any chance of having a band-pass cutting the UV, but the choices of glass types will influence this also.
Excellent info, makes my decision towards the HD model a bit more certain. Thanks for the painstaking review as well. Your contribution is highly appreciated.
06-21-2021, 05:38 AM   #28
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QuoteOriginally posted by vijaykishan Quote
Excellent info, makes my decision towards the HD model a bit more certain. Thanks for the painstaking review as well. Your contribution is highly appreciated.
A pleasure to help!

QuoteOriginally posted by StiffLegged Quote
The best thing about the HD versions of the Limiteds is that Pentax are still making them.
That's an excellent point.
06-21-2021, 06:52 AM   #29
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Thank you for the review. It looks like the new versions are a bit better. The findings about the clean starbursts you can still get with then new ones was the most interesting part. The reduced flare keeps the stars well defined.
06-28-2021, 07:17 AM   #30
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QuoteOriginally posted by JPT Quote
Thank you for the review.
A pleasure!

QuoteOriginally posted by JPT Quote
The findings about the clean starbursts you can still get with then new ones was the most interesting part. The reduced flare keeps the stars well defined.
Yes, although the SMC still ARE better for starbursts.
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