35/1.8 W-Nikkor C & 35/2 Summicron-M comparison test shots

[awilder]

Posted here: http://www.photo.net/photodb/photo?photo_id=5729855 are some comparison shots of the two lenses. Film was ISO 100 color neg. Reala for the Nikkor and Kodak Gold 100 for the Summicron. Sorry but these were taken at different dates as I sold the 'cron years ago. The 'cron is the pre-asph (version 4) and the Nikkor is the latest version from the SP 2005. Both have similarilarities in that central resolution wide open is better than stopped down to f/4 but the 'cron starts at a much higher level of resolution. Resolution tests at the right intermediate zone for example, shows greater detail wide open with the 'cron but by f/4 both lenses are close with the 'cron having slightly better contrast. Non-resolution pictures of the figurines show similar performance with both lenses at the same openings for off axis images although corner performance looks better with the 'cron to me.

[jonmanjiro]

I will post some comparison shots I took with my AIS 35/1.4 and W-Nikkor 35/1.8 when I get home later. My test shots were taken on Provia 100F film from the same batch, using a tripod and the same exposure settings, and scanned on the same Coolscan V scanner. My W-Nikkor 35/1.8 results are noticebly better than my AIS 35/1.4 results.

[VinceC]

That's interesting. I haven't noticed that kind of softness. I used to do a lot of b&w printing, where I would have noticed softness in the negative. On the other hand, I don't think that would have shown up in my shooting style, either. I don't center my subject, and as your tests showed with the statuettes, the off-axis performance of the lenses are nearly identical. If you compose with rule of thirds, the lenses are very close.

Still, I can understand awilder's concerns.

[jonmanjiro]

Here's some test shots taken with Provia 100F (without a warming filter), on a tripod, minutes after each other late one afternoon, and scanned with a Coolscan V. No post processing has been done on the crops. I metered with the FM3A and shot it in manual mode to match the SP. The colour difference is mostly due to the lenses. I prefer the richer colours of the 35/1.8.

1st Shot: full frame at f4 taken with the SP 2005 & 35/1.8


2nd Shot: f2 center crop - FM3A & AIS 35/1.4 on left, SP 2005 & 35/1.8 on right


3rd Shot: f4 centre crop - FM3A & AIS 35/1.4 on left, SP 2005 & 35/1.8 on right

[jonmanjiro]

1st Shot: full frame taken at f2.8 with SP 2005 & 35/1.8


2nd Shot: f2.8 centre crop - FM3A & AIS 35/1.4 on left, SP 2005 & 35/1.8 on right


3rd Shot: f2.8 top left corner crop - FM3A & AIS 35/1.4 on left, SP 2005 & 35/1.8 on right

[jonmanjiro]

1st Shot: full frame taken at f2.8 with SP 2005 & 35/1.8


2nd Shot: f2.8 centre crop - FM3A & AIS 35/1.4 on left, SP 2005 & 35/1.8 on right


3rd Shot: f2.8 bottom left corner crop - FM3A & AIS 35/1.4 on left, SP 2005 & 35/1.8 on right

[jonmanjiro]

Ok, that's it from me.

[awilder]

Great shots Jonmanjiro comparing the two Nikkors. I can see why you prefer the 35/1.8 to the 35/1.4. My own experience with the 35/1.4 AI/AIS when critically focused, was that it was incredibly sharp by f/2.8 over a large central radius and the only lenses I've used that came close was the 35/2 AFD Nikkor, the current 35/2 Summicron R or the 35/2 Summicron asph. Maybe my lens was a fluke but Nikon's usually pretty good about lens quality control as the 35/1.8 rf focus checked out fine on focus bracket testing. I did find using the 35/1.4 AI/AIS that the camera's split image or microprism focusing aids are typically designed with a built-in focus offset (typically around 0.05 mm) from the ground glass to shift the focus towards infinity sacrificing central sharpness but improving sharpness in the outer field where curvature of field is likely to degrade sharpness. Focusing the 35/1.4 using the ground glass portion close to the center of the frame should yield much sharper results centrally if that's of prime interest.

[MikeL]

awilder, could the rangefinder been off on the camera?

[NIKON KIU]

Originally Posted by jonmanjiro

Ok, that's it from me.

Thanks Jon-ee manjiro...
Good night
Kiu

[awilder]

No, not at all Mike. I double checked rf and lens coupling accuracy by bracketing focus in small increments and reviewed the resolution charts. The factory adjustment gave the best overall result. Defocus in one direction may help center resolution but everything else got worse. Defocus in the opposite direction worsens the center but improves the outer field.

[VinceC]

>> Defocus in one direction may help center resolution but everything else got worse. Defocus in the opposite direction worsens the center but improves the outer field.<<

A wide-angle lens focuses on an arc (actually a section of a sphere), not a plane (unless it's a flat-field lens). The arc radiates from the camera lens.

If you focus on a point 36 inches away, the edge of the field of view is 41 inches away on the long axis (usually horizontal axis), even further in the corner. That's a difference of 5 inches. The depth of field for a 35mm lens at f/2 focused at 36 inches covers only about 2 inches behind the point of focus.

When the lens is focused at 6 feet (72 inches), the long/horizontal axis is 82 inches away (a difference of 10 inches), whereas depth of field covers just 7 inches behind the point of focus.

You have to focus to 12 feet (144 inches) before depth of field covers the difference, which as that point is 20 inches (edge is 164 inches away).

This is all basic triangulation.

You solve it by focusing on the subject, then composing.

I don't know much about aspherical lenses. Do they correct the arc of focus into a plane? If so, that would make it difficult to compose using rule-of-thirds.

[VinceC]

Which is to say that edge softness is not a lens aberation. It's a lens characteristic.

[awilder]

Vince is absolutely correct about focus and I should have been more precise but I didn't want to go into too much detail because other factors like spherical aberration can also come into play especially with an early high speed wide angle design that's over 55 yrs old. "Minus" defocusing this lens very slightly in the direction of 0.9 meters and well within the f/1.8 dof marks does in fact sharpen the center resolution target at f/4 from 44+ lp/mm to 56+ lp/mm but nothing significant changes at f/2 where dof is much shallower and resolution goes from 36- lp/mm to 32+ lp/mm. My guess is that the improvement at f/4 is probably due to spherical aberration induced focus shift from f/2 to f/4 and the camera's rf or lens seating is calibrated to give best focus at the widest aperture where dof is shallowest. Further "minus" defocus (still within the f/1.8 dof marks) improves f/4 central resolution to 64- lp/mm but now f/2 central resolution drops down to 28+ lp/mm. It's just a guess, but maybe Nikon has tried to balance rf focus accuracy with aberration control to give a best compromise thoughout the aperture range.

[VinceC]

>>an early high speed wide angle design that's over 55 yrs old.<<

Actually, I believe it just turned 50 last September. The original release date was September 1956. I wonder if the reissued lens also used radioactive Lanthanum? Half-life is 60,000 years, so these lenses will be around for a long time to come.

[MikeL]

Thanks Vince and awilder for the info. On the plus side, my 35mm 1.8 was not radioactive or at least similar to background. Still looking for a user out there.....

[VinceC]

Brian Sweeney -- comedian scientist.

[awilder]

Thanks for the correct date of production Vince, I must of been in a hurry when initially looking it up.

[dreamsandart]

I was wondering too if the new Nikkor 35 has the Lanthanum glass element. Glass catalogues change and to have the exact glass in the new lens that was in the 50s original would be unusual it seems, but I would think that they made the new lens, if not equal in performance, maybe even better with more recent glass. (Maybe one of the reasons the SP/35 was only officially sold in Japan was because of European safety regulations, which a slightly radioactive Lanthanum glass may not pass.)

I understand that the 1.8/35 Nikkor was designed to be a very flat field optics - at least at longer distances which most lenses are optimized at. Sometimes with curvature of field (not the same as 'distortion'; pincushion / barrel) this can work as an advantage, in real world photography we rarely make photos of objects that are 'flat' and they have depth - and usually more than a few centimeters.

[awilder]

I reviewed my negs at f/4 and indeed the rf focus appears very accurate as I'll demonstrate. The 1st image is the figurine (shown in the earlier link) focused using the center resolution chart. Since the figurine is actually located a few inches in front of the plane of the chart, it's in accurate focus as it falls within the curved arc of focus described earlier by Vince and confimed when I swung the camera in position to focus on it. The next image is the same shot but the lens is slightly "minus" defocused by moving a point on the distance scale 1/4 of the length between the f/1.8 dof marks on the lens barrels dof scale. Note how the first image is sharper than the second defocused one.

[jonmanjiro]

Originally Posted by awilder

Great shots Jonmanjiro comparing the two Nikkors. I can see why you prefer the 35/1.8 to the 35/1.4. My own experience with the 35/1.4 AI/AIS when critically focused, was that it was incredibly sharp by f/2.8 over a large central radius and the only lenses I've used that came close was the 35/2 AFD Nikkor, the current 35/2 Summicron R or the 35/2 Summicron asph. Maybe my lens was a fluke but Nikon's usually pretty good about lens quality control as the 35/1.8 rf focus checked out fine on focus bracket testing. I did find using the 35/1.4 AI/AIS that the camera's split image or microprism focusing aids are typically designed with a built-in focus offset (typically around 0.05 mm) from the ground glass to shift the focus towards infinity sacrificing central sharpness but improving sharpness in the outer field where curvature of field is likely to degrade sharpness. Focusing the 35/1.4 using the ground glass portion close to the center of the frame should yield much sharper results centrally if that's of prime interest.

Thanks

Here's some DOF calculations for the photos I posted. At the distances and apertures I was shooting at, dof should have been enough to cover any focusing errors, if any, caused by the SLR focusing screen.

Photo 1: Sign
approx. 3.50m to target @ f2
2.99m - near limit of acceptable sharpness
4.22m - far limit of acceptable sharpness
1.22m - total depth of field

Photo 2: Sign
approx. 3.50m to target @ f4
2.61m - near limit of acceptable sharpness
5.30m - far limit of acceptable sharpness
2.69m - total depth of field

Photo 3: Food stall
approx. 8.00m to target @ f2.8
5.17m - near limit of acceptable sharpness
17.63m - far limit of acceptable sharpness
12.45m - total depth of field

Photo 4: Clock
approx. 40m to target @ f2.8
10.96m - near limit of acceptable sharpness
infinity - far limit of acceptable sharpness
infinity - total depth of field

As for the crops I posted, when I'm looking at a 4,000 dpi scan on my monitor at 100% pixel size I've calculated that its the equivalent of looking at a slide through a x41.6 loupe. Every little defect shows up.

The crops I posted above were reduced from 100% size down to approximately 70% size (from approx. 1,280 pixels down to the 900 pixel limit), the equivalent of looking at a slide through a x29 loupe. The size reduction helps the AIS 35/1.4 close the gap a bit, but the differences are still obvious. My AIS 35/1.4 is certainly no slouch, so I think these photos clearly show just how good my copy (alas sample variation does happen) of the new 35/1.8 lens is. Few other lenses I own give me these kind of sharp colourful results.

I think its highly likely that Tochigi Nikon's engineers tweaked the 35/1.8 design using modern glass in the course of the SP 2005 reissue project (how could they resist ). But I'm not pulling mine apart to find out!

Jon

[VinceC]

Usually, Nikon/Nikkor lenses have had minimal sample variation. It's been one of their strengths from the beginning.

On the other hand, the SP-5000 and new 35/1.8 are very unusual cameras in that they are actually custom-built. It is weird for a camera and lens to both be so out of whack, especially when the new S3/SP production runs have been so high-quality.

[jonmanjiro]

FWIW here's what 100% crops from a Coolscan V scan look like. On my PC its the equivalent of looking at slides with a x41.6 loupe

Both shots taken at f2.8 - FM3A & AIS 35/1.4 on left, SP 2005 & W-Nikkor 35/1.8 C on right.

[awilder]

I wonder if mine sample was a lemon? My test shots were at about 1.8 meters (1:51 repo ratio) but it's hard to believe it would make that much difference. I probably would have kept the kit if the lens was as sharp as shown above and simply serviced the shutter under warranty from the dealer.