50mm comparison - f1.7 vs f1.4

**geomez** · 03-07-2015, 10:18 AM

Originally posted by monochrome

the 50/1.4's were thought to be designed intentionally with softer edges and a sharp center area in order to create a pleasing 3D effect for a centered subject. That was a desirable artistic, aesthetically preferable goal in the 60's - subjectively, a 'good' subject image.

The 55/1.8's and 50/1.7's were designed for 'flat work' or 'copy work', i.e. they were intentionally designed to be uniformly sharp corner to corner.

Thanks for the history lesson. This makes a lot of sense to me. This explains why I prefer the f1.4 version. The low apertures create a dreamy effect.

troika · 03-07-2015, 10:46 AM

Originally posted by pinholecam

...

The very hexagonal oof highlights between f2.8-f5.6 on the f1.7 and f2 50s drives me nuts though.

...

Yep, me too. As much as I love legacy glass, it additionally makes me appreciate rounded high blade count modern lenses as well. But with legacy fast 50s, I chose 8 blades over 6 more than I chose the extra 2/3 of a stop of the 1.4.

carpents · 03-07-2015, 11:19 AM

Originally posted by monochrome

This is what I've learned over the years - actual professionals who've been active since the 60's might amplify this summary.

The general historical explanation of the difference in design goals between the 55/1.8's and 50/1.7's, and the 50/1.4's, related to their different intended purposes.

As a general rule the 50/1.4's were thought to be designed intentionally with softer edges and a sharp center area in order to create a pleasing 3D effect for a centered subject. That was a desirable artistic, aesthetically preferable goal in the 60's - subjectively, a 'good' subject image.

The 55/1.8's and 50/1.7's were designed for 'flat work' or 'copy work', i.e. they were intentionally designed to be uniformly sharp corner to corner. At the time the printing industry required an actual photographic negative of a 'paste up' from a typesetting machine. A camera was mounted to a Copipod or camera stand (a device to hold a camera precisely vertical so a flat sheet could be photographed on a photo table. A printing plate was made from the negative and mounted to the printing drum, etc. There was specialized equipment for this, but an SLR and accessories with a 'flat' lens could be used in small print shops.

Apparently, 1.7's and especially f/2.0's were marketed as 'consumer' lenses and often included as a kit lens - partially to allow increased margins on the less common 50/1.4's. A 50/2.0 of course starts nearer the naturally sharper part of the aperture range, so . . . . .

Today, with digital image viewing, our aesthetic tastes have evolved to value images that are sharp across the frame. When we compare legacy 1.2's and 1.4's to legacy 1.7's and 1.8's we are expressing our current aesthetics and forgetting the original design goals.

Would love to know if there are any 'official' statements about this. Are you (or any of the 'old guys') aware of anything or anyone?

**monochrome** · 03-07-2015, 11:43 AM - **1 Like**

I've only heard 'lessons' from older friends who've given me their screwmount Pentax stuff - they're in their late 70's now - nothing official or published. I do remember that my grandfather's print shop loft had a large machine / device that used large sheet film (up to 11x17) to make the negatives. A thin sheet of zinc was photo 'etched' at a certain number of dots per inch (a screen, if you will) from the negative. The more dots per inch the finer the print would be. Those dots held the ink, which then stuck to the paper as the drum rolled over it.

For text printing there was only dots and blank - black type and white paper, reversed. More dots meant sharper lines on the printed type, but more dots was more expensive. Jobs specified dots per inch as a compromise between quality and cost. For printed reproduction of photographs the gradations in dots by size and number defined the lightness and darkness of the printing - something like a grayscale. Those screens were also spec'ed by dots per inch. Obviously, the sharper the lens the sharper the final edges on the print could be.

In some of the legacy Pentax manuals such as for the MESuper you can actually see the dots in the pdf scans of photos - the resolution is so high the illusion disappears.

At least that''s how I remember it. I was very young at the time and my memory has faded. It was maybe 50 years ago and I was ten.

Not a Number · 03-07-2015, 12:54 PM

You got to remember too that a cropped sensor is only looking at essentially the center area of the full frame image circle. Measuring the edge and corner portions of a cropped image are not the same areas as the edge and corner of the full frame image.

osv · 03-07-2015, 09:19 PM

Originally posted by Not a Number

You got to remember too that a cropped sensor is only looking at essentially the center area of the full frame image circle. Measuring the edge and corner portions of a cropped image are not the same areas as the edge and corner of the full frame image.

^^^this

i just compared three 50's today on the a7r, the super tak 50/1.4 cleaned up quicker on the sides and corners than an md rokker-x 50/1.7 and a nikon 50/1.7.

it was also much nicer to use, with more aperture stops and better focusing action, that allowed for more degrees of rotation at the critical focus point... it actually had better center contrast wide open than the other two did, which is clearly visible with focus peaking... the focus point was the usual address numbers on the side of a building, probably a good 100 years away.

i think that lens battles are won on the sides first, then the corners... i haven't seen very many lenses that were unacceptable in the center, but a high pixel density sensor like the k3 has is going to be tougher on that than my a7r is.

yusuf · 03-08-2015, 11:40 PM

Originally posted by Not a Number

You got to remember too that a cropped sensor is only looking at essentially the center area of the full frame image circle. Measuring the edge and corner portions of a cropped image are not the same areas as the edge and corner of the full frame image.

btw, as I mentioned in the post, the pictures posted are from A7 - FF

ChristianRock · 03-10-2015, 08:15 AM - **1 Like**

I found this interesting article by Mike Johnston (known mostly for his The Online Photographer blog), at the Luminous Landscape site:

My Favorite Lens - Luminous Landscape

It is interesting that he says that the design of the join in the glued 4th and 5th elements, influences bokeh and sharpness at infinity. He says (and I don't know how correct he would be) that the 50 1.4 concave/convex surfaces yield a much better bokeh than the flat surfaces used in the Pentax 50 1.7 designs, but that the flat surfaces make the lens a bit sharper at infinity. All in all, an interesting read, especially his observation that Takumars are the smoothest focusing lenses ever made - Leica not excepted.

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03-07-2015, 10:18 AM	#16
geomez Site Supporter Join Date: Mar 2013 Location: Roanoke, Virginia, USA Photos: Gallery Posts: 1,760	Originally posted by monochrome the 50/1.4's were thought to be designed intentionally with softer edges and a sharp center area in order to create a pleasing 3D effect for a centered subject. That was a desirable artistic, aesthetically preferable goal in the 60's - subjectively, a 'good' subject image. The 55/1.8's and 50/1.7's were designed for 'flat work' or 'copy work', i.e. they were intentionally designed to be uniformly sharp corner to corner. Thanks for the history lesson. This makes a lot of sense to me. This explains why I prefer the f1.4 version. The low apertures create a dreamy effect.

03-07-2015, 10:46 AM	#17
troika Pentaxian Join Date: Dec 2012 Location: Seattle, WA USA Posts: 1,753	Originally posted by pinholecam ... The very hexagonal oof highlights between f2.8-f5.6 on the f1.7 and f2 50s drives me nuts though. ... Yep, me too. As much as I love legacy glass, it additionally makes me appreciate rounded high blade count modern lenses as well. But with legacy fast 50s, I chose 8 blades over 6 more than I chose the extra 2/3 of a stop of the 1.4.

03-07-2015, 11:19 AM	#18
carpents Veteran Member Join Date: Sep 2006 Location: West Chester, PA Photos: Gallery \| Albums Posts: 1,420	Originally posted by monochrome This is what I've learned over the years - actual professionals who've been active since the 60's might amplify this summary. The general historical explanation of the difference in design goals between the 55/1.8's and 50/1.7's, and the 50/1.4's, related to their different intended purposes. As a general rule the 50/1.4's were thought to be designed intentionally with softer edges and a sharp center area in order to create a pleasing 3D effect for a centered subject. That was a desirable artistic, aesthetically preferable goal in the 60's - subjectively, a 'good' subject image. The 55/1.8's and 50/1.7's were designed for 'flat work' or 'copy work', i.e. they were intentionally designed to be uniformly sharp corner to corner. At the time the printing industry required an actual photographic negative of a 'paste up' from a typesetting machine. A camera was mounted to a Copipod or camera stand (a device to hold a camera precisely vertical so a flat sheet could be photographed on a photo table. A printing plate was made from the negative and mounted to the printing drum, etc. There was specialized equipment for this, but an SLR and accessories with a 'flat' lens could be used in small print shops. Apparently, 1.7's and especially f/2.0's were marketed as 'consumer' lenses and often included as a kit lens - partially to allow increased margins on the less common 50/1.4's. A 50/2.0 of course starts nearer the naturally sharper part of the aperture range, so . . . . . Today, with digital image viewing, our aesthetic tastes have evolved to value images that are sharp across the frame. When we compare legacy 1.2's and 1.4's to legacy 1.7's and 1.8's we are expressing our current aesthetics and forgetting the original design goals. Would love to know if there are any 'official' statements about this. Are you (or any of the 'old guys') aware of anything or anyone?

03-07-2015, 11:43 AM - 1 Like	#19
monochrome Loyal Site Supporter Join Date: Mar 2008 Location: Working From Home Photos: Gallery \| Albums Posts: 26,276	I've only heard 'lessons' from older friends who've given me their screwmount Pentax stuff - they're in their late 70's now - nothing official or published. I do remember that my grandfather's print shop loft had a large machine / device that used large sheet film (up to 11x17) to make the negatives. A thin sheet of zinc was photo 'etched' at a certain number of dots per inch (a screen, if you will) from the negative. The more dots per inch the finer the print would be. Those dots held the ink, which then stuck to the paper as the drum rolled over it. For text printing there was only dots and blank - black type and white paper, reversed. More dots meant sharper lines on the printed type, but more dots was more expensive. Jobs specified dots per inch as a compromise between quality and cost. For printed reproduction of photographs the gradations in dots by size and number defined the lightness and darkness of the printing - something like a grayscale. Those screens were also spec'ed by dots per inch. Obviously, the sharper the lens the sharper the final edges on the print could be. In some of the legacy Pentax manuals such as for the MESuper you can actually see the dots in the pdf scans of photos - the resolution is so high the illusion disappears. At least that''s how I remember it. I was very young at the time and my memory has faded. It was maybe 50 years ago and I was ten.

03-07-2015, 12:54 PM	#20
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	You got to remember too that a cropped sensor is only looking at essentially the center area of the full frame image circle. Measuring the edge and corner portions of a cropped image are not the same areas as the edge and corner of the full frame image.

03-07-2015, 09:19 PM	#21
osv Veteran Member Join Date: Mar 2007 Location: So Cal Photos: Gallery Posts: 2,080	Originally posted by Not a Number You got to remember too that a cropped sensor is only looking at essentially the center area of the full frame image circle. Measuring the edge and corner portions of a cropped image are not the same areas as the edge and corner of the full frame image. ^^^this i just compared three 50's today on the a7r, the super tak 50/1.4 cleaned up quicker on the sides and corners than an md rokker-x 50/1.7 and a nikon 50/1.7. it was also much nicer to use, with more aperture stops and better focusing action, that allowed for more degrees of rotation at the critical focus point... it actually had better center contrast wide open than the other two did, which is clearly visible with focus peaking... the focus point was the usual address numbers on the side of a building, probably a good 100 years away. i think that lens battles are won on the sides first, then the corners... i haven't seen very many lenses that were unacceptable in the center, but a high pixel density sensor like the k3 has is going to be tougher on that than my a7r is.

03-08-2015, 11:40 PM	#22
yusuf Pentaxian Join Date: Nov 2008 Location: Palo Alto, CA Photos: Gallery Posts: 2,497 Original Poster	Originally posted by Not a Number You got to remember too that a cropped sensor is only looking at essentially the center area of the full frame image circle. Measuring the edge and corner portions of a cropped image are not the same areas as the edge and corner of the full frame image. btw, as I mentioned in the post, the pictures posted are from A7 - FF

03-10-2015, 08:15 AM - 1 Like	#23
ChristianRock Pentaxian Join Date: Jul 2013 Location: People's Republic of America Photos: Gallery \| Albums Posts: 9,910	I found this interesting article by Mike Johnston (known mostly for his The Online Photographer blog), at the Luminous Landscape site: My Favorite Lens - Luminous Landscape It is interesting that he says that the design of the join in the glued 4th and 5th elements, influences bokeh and sharpness at infinity. He says (and I don't know how correct he would be) that the 50 1.4 concave/convex surfaces yield a much better bokeh than the flat surfaces used in the Pentax 50 1.7 designs, but that the flat surfaces make the lens a bit sharper at infinity. All in all, an interesting read, especially his observation that Takumars are the smoothest focusing lenses ever made - Leica not excepted.