M240 w. Zeiss Halogen 16/8 first results

[Guest JMF]

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From your results on the M240, I guess the 16 f8 Hologon should fare better on the M246 / Monochrome v2 than it did for me  on the Monochrome v1 (CCD) .

 

With the pictures I took with a MM v1, I was spending too much time on photoshop cleaning the heavy fall off even when using the x4 ND specific  filter on the Hologon 16.

 

I remember the 21 Elmarit pre asph working much better on the M240  than on the M9 with the red corners syndrome gone when closing the shutter past f5.6 .

 

The 16 Hologon on the M8 is a nice compact daylight CCD package for sure. Please share some BW conversions !

 

On a MM v1:

 

Au Carroussel du Louvre by JM__, on Flickr

 

I nearly broke my SL 601 shutter when trying the 16 Hologon M modified when focussing at infinity (rear lens module protruding most then) so test with care or use with the "electronic shutter" mode, even on a Sony a7 !

 

on the SL 601:

 

Josef Sudek exhibition, going in ! by JM__, on Flickr

 

 

Best, JM.

Edited March 18, 2018 by JMF

[adan]

Out of curiosity, when did "Flat-field correction" come to mean "correcting for darkened corners" rather than "correcting for out-of-focus corners"?

 

Some lenses have a defect called "curvature of field" - that is, photographing a flat subject (proverbial brick wall, newspaper page), when the center of the picture is sharp, the corners are out-of-focus (but focused somewhere else not in the plane of the wall or page, not simple fuzzy).

 

https://en.wikipedia.org/wiki/Petzval_field_curvature

 

This was a serious problem when "process cameras" came into use to make negatives of pages to be printed, from which the printing plates were then burned. Or any time a camera was used to copy flat subjects - paintings, drawings, etc. So "flat-field" lenses were created.

 

There is nothing "curved" about the purple color problems with short-focus wide lenses on digital sensors (as so amply demonstrated on the previous page) - so why is that a "flat-field" correction, instead of a "color or tonal vignetting" correction?

[Guest JMF]

Out of curiosity, when did "Flat-field correction" come to mean "correcting for darkened corners" rather than "correcting for out-of-focus corners"?

 

Some lenses have a defect called "curvature of field" - that is, photographing a flat subject (proverbial brick wall, newspaper page), when the center of the picture is sharp, the corners are out-of-focus (but focused somewhere else not in the plane of the wall or page, not simple fuzzy).

 

https://en.wikipedia.org/wiki/Petzval_field_curvature

 

This was a serious problem when "process cameras" came into use to make negatives of pages to be printed, from which the printing plates were then burned. Or any time a camera was used to copy flat subjects - paintings, drawings, etc. So "flat-field" lenses were created.

 

There is nothing "curved" about the purple color problems with short-focus wide lenses on digital sensors (as so amply demonstrated on the previous page) - so why is that a "flat-field" correction, instead of a "color or tonal vignetting" correction?

 

 

I did not see fuzzy / smeared sides when shooting the 16 Hologon on the MMv1 or SL. Did not specifically check the corners .

 

On the MMv1:

 

Au Carroussel du Louvre by JM__, on Flickr

Edited March 18, 2018 by JMF

[jaapv]

Out of curiosity, when did "Flat-field correction" come to mean "correcting for darkened corners" rather than "correcting for out-of-focus corners"?

 

Some lenses have a defect called "curvature of field" - that is, photographing a flat subject (proverbial brick wall, newspaper page), when the center of the picture is sharp, the corners are out-of-focus (but focused somewhere else not in the plane of the wall or page, not simple fuzzy).

 

https://en.wikipedia.org/wiki/Petzval_field_curvature

 

This was a serious problem when "process cameras" came into use to make negatives of pages to be printed, from which the printing plates were then burned. Or any time a camera was used to copy flat subjects - paintings, drawings, etc. So "flat-field" lenses were created.

 

There is nothing "curved" about the purple color problems with short-focus wide lenses on digital sensors (as so amply demonstrated on the previous page) - so why is that a "flat-field" correction, instead of a "color or tonal vignetting" correction?

A fair question, Andy, and I certainly don't know when, but it is  indeed currently the name for the software correcting for colour shifts and vignetting.

[jmahto]

Out of curiosity, when did "Flat-field correction" come to mean "correcting for darkened corners" rather than "correcting for out-of-focus corners"?

 

Some lenses have a defect called "curvature of field" - that is, photographing a flat subject (proverbial brick wall, newspaper page), when the center of the picture is sharp, the corners are out-of-focus (but focused somewhere else not in the plane of the wall or page, not simple fuzzy).

 

https://en.wikipedia.org/wiki/Petzval_field_curvature

 

This was a serious problem when "process cameras" came into use to make negatives of pages to be printed, from which the printing plates were then burned. Or any time a camera was used to copy flat subjects - paintings, drawings, etc. So "flat-field" lenses were created.

 

There is nothing "curved" about the purple color problems with short-focus wide lenses on digital sensors (as so amply demonstrated on the previous page) - so why is that a "flat-field" correction, instead of a "color or tonal vignetting" correction?

We can certainly petition for name change of "flat field" to something better if we collect enough signatures.

 

Seriously... the phrase "flat field" does not refer to geometric shape of focus (as you are suggesting) but

 

"..to the process of compensating for different gains and dark currents in a detector." (From https://en.wikipedia.org/wiki/Flat-field_correction)

 

Flat field processing makes the output signal curve from different parts of the detector flat (my explanation).

Edited March 20, 2018 by jmahto

[harryzet]

leica sells a summaron 5,6/28 which has more vignetting - and they praise it for this. so dont worry

[Raid Amin]

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Flat field processing makes the output signal curve from different parts of the detector flat (my explanation).

This is a good explanation

[Raid Amin]

one image by the Hologon

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Edited March 24, 2018 by Raid Amin

[Raid Amin]

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[ECohen]

Very nice color on the above 4 shots.

Were they shot on your M8 ...... with the 16mm cropped edges

Or did you shoot them with  the M240 and fixed the corners with a post program?

[Raid Amin]

I used the Hologon with the M8. It is effectively a 21mm lens here. I still need to learn how to adjust the corners with a FF camera such as the M240.

[Raid Amin]

As a follow-up to my past posts on using the Hologon with the M240 and then the M8, an hour ago I tried using this lens on the recently returned M9 with a new sensor. The comparison should be for FF M240, of course. From just a few snapshots, I see more purple smear at the edges in the four sides, plus darker vignetting even when using the special ND filter. For the M9, I should maybe just use it as B&W. Somehow, the M240 does a better job with the Hologon even though there is a purple smear but less vignetting. 

[Raid Amin]

Is the new M9 sensor thicker than the M240 sensor?

Is the new firmware in the M9 very different from the firmware in the M240?

Could it be that the rear element of the Hologon gets too close to the sensor, resulting in the purple smear?

Oh well. I got myself into this.

[adan]

I think its a redesign of the microlenses in the CMOS sensors (M240 family maybe, M10 definitely) that has - slightly - improved the color stains with wide lenses. I've acquired 35 and 28 v.2 lenses (ca. 1970 designs) and they produce less color staining on the M10 CMOS than they did on the CCD M9 (with either original or replacement sensor). Virtually none with the 35, minimal with the 28 (you'd need to shoot blank walls or snowy fields to see it).

[Raid Amin]

Thanks for your input, Andy.

I will (as a first step) use the Hologon on the M9 and then remove all colors.

The CCD sensor is after all more affected than the CMOS sensor. I was hoping for the opposite to  happen, but that was wishful thinking from me.

You see such (minimal) effects with your 28mm lens. I may encounter "snow fields" this summer!

When I use the lens with the M8, I do not see the purple smear at a 21mm crop. It may be minimal and I don't observe it.

[Raid Amin]

I took additional photos with the M9 and Zeiss lens, and the dark vignetting is very obvious even with the ND filter in place. It seems to barely reduce the darkness a little.

[Raid Amin]

I tried again with the new sensor in the M9 and with "B&W".

 

 

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Hallo,

Look here: Leica M

[Raid Amin]

I tried overexposing by 1 f stop. I tried taking the ND filter off. I tried what was possible to do. Color images need special treatment, it seems.  I start with B&W.