HD FA35 f/2 vs FA35 f/2 - hybrid aspherical vs ground glass aspherical element?

**BigMackCam** · 02-04-2019, 05:13 PM

Originally posted by nocturnal

So Sony's new asph fabrication developments result in smaller and cheaper lenses. This is where it is at then and I don't like monster lenses if they don't have to be as big or costly.

I didn't read anything in that article that suggests Sony's methods will make lenses physically smaller. Just that the aspherical elements they're producing (or will produce) shouldn't suffer from the ridges inherent on some others, and that they can estimate the quality of out-of-focus rendering ("bokeh") during the design process, and before a lens is tested.

TL;DR... You can't make a small, light, full frame 24-70 f/2.8 out of decent materials. Because physics

nocturnal · 02-04-2019, 05:52 PM

Originally posted by BigMackCam

I didn't read anything in that article that suggests Sony's methods will make lenses physically smaller. Just that the aspherical elements they're producing (or will produce) shouldn't suffer from the ridges inherent on some others, and that they can estimate the quality of out-of-focus rendering ("bokeh") during the design process, and before a lens is tested.

TL;DR... You can't make a small, light, full frame 24-70 f/2.8 out of decent materials. Because physics

It is in there about 1/3 - 1/2 way down the page just below the cutaway photo of the 85mm f1.4 which consequently 'only' weighs 820g which is lighter and smaller than the Pentax DFA 50mm f1.4.

---------- Post added 02-05-19 at 01:12 AM ----------

After reading the article it makes you wonder about using a 1999 lens design like the 35/2.

The modern Pentax lenses I think produce much nicer bokeh than the legacy designs, the HD DA Limiteds and all the new DFA lenses do it so well. If I'm back looking at pentagons/hexagons again well no I don't want to do that. I have a certain photo taken with the K35/3.5 with a massive pentagon right in the middle of it, I think it's time to move all these lenses on while they are still worth a bit of cash.

**BigMackCam** · 02-04-2019, 06:12 PM - **3 Likes**

Originally posted by nocturnal

It is in there about 1/3 - 1/2 way down the page just below the cutaway photo of the 85mm f1.4 which consequently 'only' weighs 820g which is lighter and smaller than the Pentax DFA 50mm f1.4.

Ah, OK. Honestly. I wouldn't build up hopes on that too much just yet. Firstly, Sony doesn't have the monopoly on clever optical design, and then - as I said before - there's physics, and optical complexity, which will dictate minimum size of lenses. I'm sure Sony is doing a fine job, but I doubt it can produce a D*FA50/1.4 competitor that is optically as capable and physically much smaller or lighter without sacrificing quality. If it can, where is it?

**twilhelm** · 02-04-2019, 06:59 PM

The article doesn't specify that the new process will make all of their lenses smaller / lighter. Only that the 85 would have been extremely heavy with all the correction elements needed to get what they wanted.

nocturnal · 02-04-2019, 07:26 PM

Originally posted by twilhelm

The article doesn't specify that the new process will make all of their lenses smaller / lighter. Only that the 85 would have been extremely heavy with all the correction elements needed to get what they wanted.

It says this: "Extreme Aspherical elements for more compact, higher-performing lenses"

I imagine it would work for others too, why not? The Sony 70-200 f2.8 is lighter than the DFA* 70-200 f2.8 but size is about the same.

I don't know how well the Sony does against the DFA *50 f1.4 but I think it is possibly the best 50mm out there. I wonder how heavy the Pentax DFA* 85mm f1.4 version is going to be? Certainly heavier than 820g I would think but maybe better too.

If there is tech to make smaller and lighter for the same IQ I'm all for it.

I'll not be buying anything in that price range but the tech is interesting. ��

---------- Post added 02-05-19 at 02:33 AM ----------

BTW I know that certain focal length speeds and apertures require a minimum diameter but using less complex design could make lenses shorter. No certainly Sony does not have a monopoly with optics, maybe just this articles aspect of certain patents. I'm sure Pentax has 100s patents on camera gear.

beholder3 · 02-05-2019, 12:43 AM

Originally posted by nocturnal

It says this: "Extreme Aspherical elements for more compact, higher-performing lenses"
...
If there is tech to make smaller and lighter for the same IQ I'm all for it.

There is a systematic problem with molded aspherical lenses until today and that is ugly bokeh, damaged by onion rings.
See: https://www.imaging-resource.com/news/2014/05/02/the-end-of-onion-ring-bokeh...spheric-lenses

Modern extra expensive (and not light or small) Zeiss lenses have this poor bokeh: http://www.verybiglobo.com/wp-content/uploads/2016/03/55_Crop_f14PD.jpg and it is caused by aspherical elements.

It is easy to correct certain optical flaws, but onion ring bokeh is not one of them.

Sigma lenses also have the problem due to the same reasons.

---------- Post added 5th Feb 2019 at 08:47 ----------

Originally posted by Digitalis

The nature of the polymer Zeiss is using for these lenses is unknown. It would be unlikely to be used in lens construction, as the properties of contact lenses and the requirements for bio-compatibility would make them different from what is required from precision optical elements.

The materials I linked to are for "glasses" not contact lenses. (I struggle with English language here) I would not expect them to have vastly different requirements to lens elements in photo lenses.

**Digitalis** · 02-05-2019, 04:42 PM

Originally posted by beholder3

Zeiss for example offers non-glass organic "plastic" lenses for human vision between index ranges from 1.5 to 1.74

Originally posted by beholder3

The materials I linked to are for "glasses" not contact lenses.

Exactly what are you going on about here? optical plastics or glass?

Andrea K · 02-06-2019, 02:45 AM

The A* 85 f/1,4 is very compact, has no rivals and has no special elements inside.

**clackers** · 02-06-2019, 04:12 AM - **1 Like**

Originally posted by Andrea K

The A* 85 f/1,4 is very compact, has no rivals and has no special elements inside.

I think we'll find the DFA* 85 f1.4 will be sensational, Andrea.

Won't be compact or cheap, though.

**TwoUptons** · 02-06-2019, 08:50 AM

Originally posted by Digitalis

Exactly what are you going on about here? optical plastics or glass?

I thought he was talking about eyeglasses, which are often made of optical plastics.

I used to have a pair of glasses with SMC coatings, 25 years ago... that was awesome, especially at night...

-Eric

Andrea K · 02-07-2019, 02:17 AM

Originally posted by clackers

I think we'll find the DFA* 85 f1.4 will be sensational, Andrea.

Won't be compact or cheap, though.

Surely

beholder3 · 02-07-2019, 08:05 AM

Originally posted by Digitalis

Exactly what are you going on about here? optical plastics or glass?

After looking into the dictionary:

I tried pointing out that the Zeiss material is used for spectacles (which mean large elements out of rock solid material and with virtually no contact to the body). Not for contact lenses which - as far as I know - either are made from solid glass or soft plastics.
And the lens material for spectacles in my little opinion has pretty similar requirements as photo lens material.

gm4life · 02-07-2019, 05:46 PM

Originally posted by clackers

I think we'll find the DFA* 85 f1.4 will be sensational, Andrea.

Won't be compact or cheap, though.

All true... I am completely agree and am looking forward to adding it to my collection yet in 2019. For now the FA 35 HD will have to tie my over!

**clackers** · 02-07-2019, 06:59 PM

Originally posted by gm4life

All true... I am completely agree and am looking forward to adding it to my collection yet in 2019. For now the FA 35 HD will have to tie my over!

There's a lot to love about it.

**monochrome** · 02-07-2019, 07:01 PM

Originally posted by TwoUptons

I thought he was talking about eyeglasses, which are often made of optical plastics.

I used to have a pair of glasses with SMC coatings, 25 years ago... that was awesome, especially at night...

-Eric

The B&M shop where I get my eyeglasses made still has Pentax table cards and notepads and a wall clock.

02-05-2019, 12:43 AM	#36
beholder3 Pentaxian Join Date: Dec 2011 Posts: 3,112	Originally posted by nocturnal It says this: "Extreme Aspherical elements for more compact, higher-performing lenses" ... If there is tech to make smaller and lighter for the same IQ I'm all for it. There is a systematic problem with molded aspherical lenses until today and that is ugly bokeh, damaged by onion rings. See: https://www.imaging-resource.com/news/2014/05/02/the-end-of-onion-ring-bokeh...spheric-lenses Modern extra expensive (and not light or small) Zeiss lenses have this poor bokeh: http://www.verybiglobo.com/wp-content/uploads/2016/03/55_Crop_f14PD.jpg and it is caused by aspherical elements. It is easy to correct certain optical flaws, but onion ring bokeh is not one of them. Sigma lenses also have the problem due to the same reasons. ---------- Post added 5th Feb 2019 at 08:47 ---------- Originally posted by Digitalis The nature of the polymer Zeiss is using for these lenses is unknown. It would be unlikely to be used in lens construction, as the properties of contact lenses and the requirements for bio-compatibility would make them different from what is required from precision optical elements. The materials I linked to are for "glasses" not contact lenses. (I struggle with English language here) I would not expect them to have vastly different requirements to lens elements in photo lenses. Last edited by beholder3; 02-05-2019 at 12:53 AM.

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02-04-2019, 05:13 PM	#31
BigMackCam Digitiser of Film Join Date: Mar 2010 Location: North East of England Posts: 20,670 Original Poster	Originally posted by nocturnal So Sony's new asph fabrication developments result in smaller and cheaper lenses. This is where it is at then and I don't like monster lenses if they don't have to be as big or costly. I didn't read anything in that article that suggests Sony's methods will make lenses physically smaller. Just that the aspherical elements they're producing (or will produce) shouldn't suffer from the ridges inherent on some others, and that they can estimate the quality of out-of-focus rendering ("bokeh") during the design process, and before a lens is tested. TL;DR... You can't make a small, light, full frame 24-70 f/2.8 out of decent materials. Because physics

02-04-2019, 05:52 PM	#32
nocturnal Veteran Member Join Date: Dec 2012 Photos: Gallery Posts: 507	Originally posted by BigMackCam I didn't read anything in that article that suggests Sony's methods will make lenses physically smaller. Just that the aspherical elements they're producing (or will produce) shouldn't suffer from the ridges inherent on some others, and that they can estimate the quality of out-of-focus rendering ("bokeh") during the design process, and before a lens is tested. TL;DR... You can't make a small, light, full frame 24-70 f/2.8 out of decent materials. Because physics It is in there about 1/3 - 1/2 way down the page just below the cutaway photo of the 85mm f1.4 which consequently 'only' weighs 820g which is lighter and smaller than the Pentax DFA 50mm f1.4. ---------- Post added 02-05-19 at 01:12 AM ---------- After reading the article it makes you wonder about using a 1999 lens design like the 35/2. The modern Pentax lenses I think produce much nicer bokeh than the legacy designs, the HD DA Limiteds and all the new DFA lenses do it so well. If I'm back looking at pentagons/hexagons again well no I don't want to do that. I have a certain photo taken with the K35/3.5 with a massive pentagon right in the middle of it, I think it's time to move all these lenses on while they are still worth a bit of cash.

02-04-2019, 06:12 PM - 3 Likes	#33
BigMackCam Digitiser of Film Join Date: Mar 2010 Location: North East of England Posts: 20,670 Original Poster	Originally posted by nocturnal It is in there about 1/3 - 1/2 way down the page just below the cutaway photo of the 85mm f1.4 which consequently 'only' weighs 820g which is lighter and smaller than the Pentax DFA 50mm f1.4. Ah, OK. Honestly. I wouldn't build up hopes on that too much just yet. Firstly, Sony doesn't have the monopoly on clever optical design, and then - as I said before - there's physics, and optical complexity, which will dictate minimum size of lenses. I'm sure Sony is doing a fine job, but I doubt it can produce a D*FA50/1.4 competitor that is optically as capable and physically much smaller or lighter without sacrificing quality. If it can, where is it?

02-04-2019, 06:59 PM	#34
twilhelm Loyal Site Supporter Join Date: Feb 2009 Location: Florida Photos: Gallery \| Albums Posts: 2,369	The article doesn't specify that the new process will make all of their lenses smaller / lighter. Only that the 85 would have been extremely heavy with all the correction elements needed to get what they wanted.

02-04-2019, 07:26 PM	#35
nocturnal Veteran Member Join Date: Dec 2012 Photos: Gallery Posts: 507	Originally posted by twilhelm The article doesn't specify that the new process will make all of their lenses smaller / lighter. Only that the 85 would have been extremely heavy with all the correction elements needed to get what they wanted. It says this: "Extreme Aspherical elements for more compact, higher-performing lenses" I imagine it would work for others too, why not? The Sony 70-200 f2.8 is lighter than the DFA* 70-200 f2.8 but size is about the same. I don't know how well the Sony does against the DFA 50 f1.4 but I think it is possibly the best 50mm out there. I wonder how heavy the Pentax DFA 85mm f1.4 version is going to be? Certainly heavier than 820g I would think but maybe better too. If there is tech to make smaller and lighter for the same IQ I'm all for it. I'll not be buying anything in that price range but the tech is interesting. �� ---------- Post added 02-05-19 at 02:33 AM ---------- BTW I know that certain focal length speeds and apertures require a minimum diameter but using less complex design could make lenses shorter. No certainly Sony does not have a monopoly with optics, maybe just this articles aspect of certain patents. I'm sure Pentax has 100s patents on camera gear.

02-05-2019, 04:42 PM	#37
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by beholder3 Zeiss for example offers non-glass organic "plastic" lenses for human vision between index ranges from 1.5 to 1.74 Originally posted by beholder3 The materials I linked to are for "glasses" not contact lenses. Exactly what are you going on about here? optical plastics or glass?

02-06-2019, 02:45 AM	#38
Andrea K Pentaxian Join Date: Mar 2009 Location: Rome, Italy Posts: 822	The A* 85 f/1,4 is very compact, has no rivals and has no special elements inside.

02-06-2019, 04:12 AM - 1 Like	#39
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by Andrea K The A* 85 f/1,4 is very compact, has no rivals and has no special elements inside. I think we'll find the DFA* 85 f1.4 will be sensational, Andrea. Won't be compact or cheap, though.

02-06-2019, 08:50 AM	#40
TwoUptons Loyal Site Supporter Join Date: Nov 2015 Photos: Albums Posts: 4,213	Originally posted by Digitalis Exactly what are you going on about here? optical plastics or glass? I thought he was talking about eyeglasses, which are often made of optical plastics. I used to have a pair of glasses with SMC coatings, 25 years ago... that was awesome, especially at night... -Eric

02-07-2019, 02:17 AM	#41
Andrea K Pentaxian Join Date: Mar 2009 Location: Rome, Italy Posts: 822	Originally posted by clackers I think we'll find the DFA* 85 f1.4 will be sensational, Andrea. Won't be compact or cheap, though. Surely

02-07-2019, 08:05 AM	#42
beholder3 Pentaxian Join Date: Dec 2011 Posts: 3,112	Originally posted by Digitalis Exactly what are you going on about here? optical plastics or glass? After looking into the dictionary: I tried pointing out that the Zeiss material is used for spectacles (which mean large elements out of rock solid material and with virtually no contact to the body). Not for contact lenses which - as far as I know - either are made from solid glass or soft plastics. And the lens material for spectacles in my little opinion has pretty similar requirements as photo lens material.

02-07-2019, 05:46 PM	#43
gm4life Veteran Member Join Date: Dec 2016 Posts: 602	Originally posted by clackers I think we'll find the DFA* 85 f1.4 will be sensational, Andrea. Won't be compact or cheap, though. All true... I am completely agree and am looking forward to adding it to my collection yet in 2019. For now the FA 35 HD will have to tie my over!

02-07-2019, 06:59 PM	#44
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by gm4life All true... I am completely agree and am looking forward to adding it to my collection yet in 2019. For now the FA 35 HD will have to tie my over! There's a lot to love about it.

02-07-2019, 07:01 PM	#45
monochrome Loyal Site Supporter Join Date: Mar 2008 Location: Working From Home Photos: Gallery \| Albums Posts: 26,276	Originally posted by TwoUptons I thought he was talking about eyeglasses, which are often made of optical plastics. I used to have a pair of glasses with SMC coatings, 25 years ago... that was awesome, especially at night... -Eric The B&M shop where I get my eyeglasses made still has Pentax table cards and notepads and a wall clock.