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Quick and dirty image circle comparisons
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PostPosted: Sun Jun 03, 2018 2:05 pm    Post subject: Reply with quote

It still concerns image circle sizes, so this tangent is totally fine with me. Do you get a larger image circle with this MSC than with other 1,4x teleconverters? When you say full shift coverage, how many mm are we talking?

In the photo with the MSC and the 150 PN it looks like there is a bit of LoCA in the background. Is this also present when using the Printing Nikkor without MSC? Is your 150 PN the earlier version with 62mm threads or the later one with 58mm threads?


PostPosted: Sun Jun 03, 2018 2:22 pm    Post subject: Reply with quote

dickb wrote:
It still concerns image circle sizes, so this tangent is totally fine with me. Do you get a larger image circle with this MSC than with other 1,4x teleconverters? When you say full shift coverage, how many mm are we talking?

In the photo with the MSC and the 150 PN it looks like there is a bit of LoCA in the background. Is this also present when using the Printing Nikkor without MSC? Is your 150 PN the earlier version with 62mm threads or the later one with 58mm threads?


You don't get a larger image circle with other TCs, just the same circle of a smaller part of the image blown up. The MSC will give 42mm, as opposed to standard 43mm for 35mm film lenses.

I haven't done much with this setup. The MSC corrects common aberrations in wide angle lenses and was never meant to be used with 150mm so it might put a few in! Who wants to shift a 150mm? It was just a way to get around a particular problem, the shift being of no interest here.

The PN images here are to demonstrate how it make the image circle larger, not as a recommended use.

The PN has 62mm threads.


PostPosted: Sun Jun 03, 2018 2:49 pm    Post subject: Reply with quote

e6filmuser wrote:
You don't get a larger image circle with other TCs, just the same circle of a smaller part of the image blown up. The MSC will give 42mm, as opposed to standard 43mm for 35mm film lenses.


Like you say, teleconverters blow up the image. If the TC doesn't cause vignetting with baffles or something, the image circle will be larger.


e6filmuser wrote:
I haven't done much with this setup. The MSC corrects common aberrations in wide angle lenses and was never meant to be used with 150mm so it might put a few in! Who wants to shift a 150mm? It was just a way to get around a particular problem, the shift being of no interest here.



It is always interesting to use things in ways they weren't intended for. I'm just saying that using a normal 1.4x TC may well give you better results with the 150 PN than the MSC

e6filmuser wrote:
The PN has 62mm threads.


So it is the early version with the magnification optimising ring, should be a great performer over a wider magnification range than the later one.


PostPosted: Sun Jun 03, 2018 3:09 pm    Post subject: Reply with quote

dickb wrote:


Like you say, teleconverters blow up the image. If the TC doesn't cause vignetting with baffles or something, the image circle will be larger.


Yes but it blows up the image from the middle of the lens, giving "normal size" for that part of the image, not a larger than normal one. That would spread the image in the dark areas, outside the frame, effectively losing it in designed-for applications. (I have checked for this on other occasions).

dickb wrote:
It is always interesting to use things in ways they weren't intended for. I'm just saying that using a normal 1.4x TC may well give you better results with the 150 PN than the MSC


Yes but not across the whole frame.

e6filmuser wrote:
The PN has 62mm threads.


So it is the early version with the magnification optimising ring, should be a great performer over a wider magnification range than the later one.[/quote]

That's right 1:4 to 4:1, ideally not outside 1:2 to 2:1 (full frame). It weighs over 1kg so I don't normally take it on field trips. Its working distance is very long, making framing difficult.


PostPosted: Sun Jun 03, 2018 3:23 pm    Post subject: Reply with quote

This might be of interest. Of:

Schneider-Kreuznach Photographic Enlarging Lenses

APO-Componon HM series.

These are 6-element, 4-group apochromatic enlarger lenses, using high-modulation glass elements,
designed for critical colour rendition and precision industrial applications.
・40mm F2.8
・45mm F4
・60mm F4
・90mm F4.5
・120mm F5.6
・150mm F4

I have the 40mm and the 90mm for macro. The 40 covers 35mm format and the 90 something like 60 x66mm (I can't find the original source at the moment).


PostPosted: Sun Jun 03, 2018 7:16 pm    Post subject: Reply with quote

For enlarger lenses the official literature normally states what size negative they can be used with. This is not always exactly the same as how large the image circle is when the lens is used as a taking lens focussed at infinity. All enlarger lenses I tried so far of 50mm or longer filled the frame of a 24x36mm camera. Shorter focal lengths often show vignetting. That is why I was interested in seeing whether a 40/2.8 focussed at infinity would cover 24x36mm.


PostPosted: Sun Jun 03, 2018 7:46 pm    Post subject: Reply with quote

dickb wrote:
That is why I was interested in seeing whether a 40/2.8 focussed at infinity would cover 24x36mm.


For anyone who doesn't know, that lens requires 39mm extension for infinity focus on m4/3.


PostPosted: Fri Dec 14, 2018 4:17 pm    Post subject: Reply with quote

And in the series of quick and literally dirty image size comparisons now two Schneider lenses in Robot Screw mount (M26), a Xenar 37.5mm f/2.8 and a Xenon 40mm f/1.9. I was surprised about how close they come to fill the Sony A7 full frame sensor, given that they were intended for 24x24mm cameras. I used a combination of adapters, M26 to M42, M42 helicoid to Sony E, which doesn't allow exact infinity focus, so these images are just rough image size estimations, not intended for image quality comparison.


Robot Schneider Kreuznach Xenar 1:2.8/37.5




Robot Schneider Kreuznach Xenon 1:1.9/40



PostPosted: Fri Dec 14, 2018 4:23 pm    Post subject: Reply with quote

e6filmuser wrote:
This might be of interest. Of:

Schneider-Kreuznach Photographic Enlarging Lenses

APO-Componon HM series.

These are 6-element, 4-group apochromatic enlarger lenses, using high-modulation glass elements,
designed for critical colour rendition and precision industrial applications.
・40mm F2.8
・45mm F4
・60mm F4
・90mm F4.5
・120mm F5.6
・150mm F4

I have the 40mm and the 90mm for macro. The 40 covers 35mm format and the 90 something like 60 x66mm (I can't find the original source at the moment).


Thanks but there are no "high-modulation glass elements", there are only glass elements which achieve high modulation in the resulting images Wink

Excellent lenses indeed, I have a few myself!


PostPosted: Fri Dec 14, 2018 4:31 pm    Post subject: Reply with quote

kds315* wrote:


Thanks but there are no "high-modulation glass elements", there are only glass elements which achieve high modulation in the resulting images Wink

Excellent lenses indeed, I have a few myself!


Not my words! I just quoted them.Smile


PostPosted: Thu Mar 14, 2019 4:49 pm    Post subject: Reply with quote

And another example from the Schneider Kreuznach Xenoplan machine vision C mount lenses, this time a 17mm f/1.4: