KP custom，DFA*85/1.4 CP+ Exhibit

**yucatanPentax** · 02-26-2019, 12:49 AM

That custom KP looks awesome. Looking forward hearing more about it.

**sbh** · 02-26-2019, 01:07 AM

The prism housing looks good...

Class A · 02-26-2019, 01:25 AM - **1 Like**

Originally posted by biz-engineer

Petal style is better optically,

The petal-style hood design is only better with respect to a given size/weight.

One could make the current hood slightly larger by adding the petal-shaped bits and that would help a bit, but it would also mean that the hood becomes larger/heavier (and less useful to place the lens/camera combo on).
Alternatively, they could have made a larger round hood and also improved on the current one, without using petal-shaped bits; it would have just be a little bit heavier than the optimal petal-shaped design.

It's just a size/weight matter, not one of "better optically".

Looking forward to seeing first shots from this lens. An unknown market launch date does not suggest it will be any time soon, though.

ebk · 02-26-2019, 02:05 AM

and oldie and a remake

hoerah for the non fantasie of 100 years pentax

repaap · 02-26-2019, 02:22 AM

Originally posted by ebk

and oldie and a remake

hoerah for the non fantasie of 100 years pentax

Glad that someone said it out loud

. New modelled KP is oldie little remade. But might give us a idea of how handle will evolve in future.

biz-engineer · 02-26-2019, 02:35 AM

Originally posted by Class A

The petal-style hood design is only better with respect to a given size/weight.

My understanding is that circular hood has to be wide enough so that it doesn't create vignetting for the long side of the 3:2 rectangle, and the circular shape is therefore too wide to equally protect the short side of the image rectangle. So, if my understanding is correct, the petal shaped hood provides better optical protection vs the circular one. Where is my thinking faulty?

rawr · 02-26-2019, 02:35 AM

Originally posted by Thagomizer

I think this pattern of three circular openings is a decorative motif. It appeared in more places on the original posting of this custom design KP

Aha. Could be just decoration or grip improvement. Also looks like stereo speaker openings (?).

Dericali · 02-26-2019, 02:45 AM

is the news on the *85 that they are showing a mock-up but probably delaying the launch?

The road map is for 2019, now market launch is 'undecided'?

Tashbir · 02-26-2019, 02:50 AM

Looking forward to the DFA* 85mmf1.4. Will be my next purchase. I'm very happy with Pentax-D FA* 50mm f1.4. I truly hope that 85mm f1.4 will reach the same level, and it can replace the old Pentax-A 85mm f1.4 in my camera bag.

**clackers** · 02-26-2019, 02:54 AM - **1 Like**

Originally posted by biz-engineer

My understanding is that circular hood has to be wide enough so that it doesn't create vignetting for the long side of the 3:2 rectangle, and the circular shape is therefore too wide to equally protect the short side of the image rectangle. So, if my understanding is correct, the petal shaped hood provides better optical protection vs the circular one. Where is my thinking faulty?

Petal hoods seem to be favoured on wider angle lenses.

biz-engineer · 02-26-2019, 03:10 AM - **2 Likes**

Originally posted by clackers

Petal hoods seem to be favoured on wider angle lenses.

Yes, I noticed the same thing. I guess wide angle lenses are more sensitive to flare, a lesser issue with 85mm... except some people like LeRolls to shoot top models with an 85mm against the sun.
On super tele lenses, the big hood makes it bigger, looking more like a 600 f4 when you only have the money for the 150-600

**clackers** · 02-26-2019, 03:29 AM - **1 Like**

Originally posted by biz-engineer

Yes, I noticed the same thing. I guess wide angle lenses are more sensitive to flare, a lesser issue with 85mm...

Yeah, I think it's more a vignetting issue.

In a very wide angle lens, the front element is huge - it can even bulge outwards.

A petal hood is just letting in a bit more light in the four corners, of course making it more vulnerable to flare there.

MMVIII · 02-26-2019, 03:42 AM - **1 Like**

I would see it like this: in a tele lens the petals of the hood could be enormously long. If you make the hood exactly that long that you don't need to cut out the corners it can stay round. It is not the maximum possible length but flare and straylight are a lesser problem anyway and one main purpose is to avoid e.g. direct sunlight on the front element.

funkythiru · 02-26-2019, 04:46 AM

Wonder if Tokina will partner up on this 85mm with Pentax?

Mistral75 · 02-26-2019, 04:51 AM

That would be wise for both but it takes two to tango...

02-26-2019, 02:35 AM	#36
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,228	Originally posted by Class A The petal-style hood design is only better with respect to a given size/weight. My understanding is that circular hood has to be wide enough so that it doesn't create vignetting for the long side of the 3:2 rectangle, and the circular shape is therefore too wide to equally protect the short side of the image rectangle. So, if my understanding is correct, the petal shaped hood provides better optical protection vs the circular one. Where is my thinking faulty? Last edited by biz-engineer; 02-26-2019 at 02:41 AM.

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02-26-2019, 12:49 AM	#31
yucatanPentax Loyal Site Supporter Join Date: Dec 2009 Location: Dallas / Yucatan Posts: 1,839	That custom KP looks awesome. Looking forward hearing more about it.

02-26-2019, 01:07 AM	#32
sbh Site Supporter Join Date: Oct 2012 Location: Black Forest, Germany Photos: Gallery Posts: 849	The prism housing looks good...

02-26-2019, 01:25 AM - 1 Like	#33
Class A Pentaxian Join Date: Aug 2008 Location: Wellington, New Zealand Posts: 11,251	Originally posted by biz-engineer Petal style is better optically, The petal-style hood design is only better with respect to a given size/weight. One could make the current hood slightly larger by adding the petal-shaped bits and that would help a bit, but it would also mean that the hood becomes larger/heavier (and less useful to place the lens/camera combo on). Alternatively, they could have made a larger round hood and also improved on the current one, without using petal-shaped bits; it would have just be a little bit heavier than the optimal petal-shaped design. It's just a size/weight matter, not one of "better optically". Looking forward to seeing first shots from this lens. An unknown market launch date does not suggest it will be any time soon, though.

02-26-2019, 02:05 AM	#34
ebk Loyal Site Supporter Join Date: Aug 2011 Location: Utrecht Posts: 148	and oldie and a remake hoerah for the non fantasie of 100 years pentax

02-26-2019, 02:22 AM	#35
repaap Pentaxian Join Date: Oct 2010 Photos: Gallery \| Albums Posts: 6,242	Originally posted by ebk and oldie and a remake hoerah for the non fantasie of 100 years pentax Glad that someone said it out loud . New modelled KP is oldie little remade. But might give us a idea of how handle will evolve in future.

02-26-2019, 02:35 AM	#37
rawr Veteran Member Join Date: Jun 2009 Posts: 11,913	Originally posted by Thagomizer I think this pattern of three circular openings is a decorative motif. It appeared in more places on the original posting of this custom design KP Aha. Could be just decoration or grip improvement. Also looks like stereo speaker openings (?).

02-26-2019, 02:45 AM	#38
Dericali Senior Member Join Date: Jul 2016 Location: Berlin Posts: 298	is the news on the *85 that they are showing a mock-up but probably delaying the launch? The road map is for 2019, now market launch is 'undecided'?

02-26-2019, 02:50 AM	#39
Tashbir New Member Join Date: Jan 2019 Posts: 18	Looking forward to the DFA* 85mmf1.4. Will be my next purchase. I'm very happy with Pentax-D FA* 50mm f1.4. I truly hope that 85mm f1.4 will reach the same level, and it can replace the old Pentax-A 85mm f1.4 in my camera bag.

02-26-2019, 02:54 AM - 1 Like	#40
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by biz-engineer My understanding is that circular hood has to be wide enough so that it doesn't create vignetting for the long side of the 3:2 rectangle, and the circular shape is therefore too wide to equally protect the short side of the image rectangle. So, if my understanding is correct, the petal shaped hood provides better optical protection vs the circular one. Where is my thinking faulty? Petal hoods seem to be favoured on wider angle lenses.

02-26-2019, 03:10 AM - 2 Likes	#41
biz-engineer Pentaxian Join Date: Feb 2015 Photos: Gallery Posts: 12,228	Originally posted by clackers Petal hoods seem to be favoured on wider angle lenses. Yes, I noticed the same thing. I guess wide angle lenses are more sensitive to flare, a lesser issue with 85mm... except some people like LeRolls to shoot top models with an 85mm against the sun. On super tele lenses, the big hood makes it bigger, looking more like a 600 f4 when you only have the money for the 150-600

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02-26-2019, 03:29 AM - 1 Like	#42
clackers Otis Memorial Pentaxian Join Date: Jul 2013 Location: Melbourne Photos: Albums Posts: 16,397	Originally posted by biz-engineer Yes, I noticed the same thing. I guess wide angle lenses are more sensitive to flare, a lesser issue with 85mm... Yeah, I think it's more a vignetting issue. In a very wide angle lens, the front element is huge - it can even bulge outwards. A petal hood is just letting in a bit more light in the four corners, of course making it more vulnerable to flare there.

02-26-2019, 03:42 AM - 1 Like	#43
MMVIII Pentaxian Join Date: Mar 2008 Location: EU Posts: 1,121	I would see it like this: in a tele lens the petals of the hood could be enormously long. If you make the hood exactly that long that you don't need to cut out the corners it can stay round. It is not the maximum possible length but flare and straylight are a lesser problem anyway and one main purpose is to avoid e.g. direct sunlight on the front element.

02-26-2019, 04:46 AM	#44
funkythiru Senior Member Join Date: Feb 2017 Location: Chicago Posts: 291	Wonder if Tokina will partner up on this 85mm with Pentax?

02-26-2019, 04:51 AM	#45
Mistral75 Pentaxian Join Date: Feb 2009 Location: Paris, France Posts: 7,526	That would be wise for both but it takes two to tango...