Beat this in sharpness

[j tokarz]

Stunning.

 

[JimKasson]

see with earlier post. Cheers.

I've looked at the Cambo Actus for GFX but I don't really know anything about the lenses being offered. Your description of the 110xl in conjunction with your pic got my curiosity up but the modifications are frankly worrisome. I'll have to look but I wonder if the Cambo has a lens board for these Schnieder lenses.

They do indeed make a plate with a #1 hole.

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www.cambo.com

You want the ACB-1.

Jim

 

[Rick Knepper]

In general the sweet spot for any lens begins 3 or 4 notches from wide open.

I always heard it as 2 stops on the Canon forum. That might have been true for their big Whites which I've never used but Canon's WA lenses circa 2003 were more like 3-4 stops. But, I rented the Zeiss Otus 55/1.4 and realized that this old conventional wisdom doesn't have to be. With this lens, f1.4 was as sharp in the corners as my Canons were at f8. A lens doesn't have to incur diffraction to get the corners in focus. All it takes are customers with money and a company willing to service that market.

 

[JimKasson]

In general the sweet spot for any lens begins 3 or 4 notches from wide open.

I always heard it as 2 stops on the Canon forum. That might have been true for their big Whites which I've never used but Canon's WA lenses circa 2003 were more like 3-4 stops. But, I rented the Zeiss Otus 55/1.4 and realized that this old conventional wisdom doesn't have to be. With this lens, f1.4 was as sharp in the corners as my Canons were at f8. A lens doesn't have to incur diffraction to get the corners in focus. All it takes are customers with money and a company willing to service that market.

The Otus 55/1.4 performance is OK wide open, and spectacular stopped down to f/2.

Jim

 

[rospotte]

copy and paste...

In general, this sweet spot is between two or three stops down from the maximum aperture. For example, for a lens that has a maximum aperture of f/1.4, the sweetspot normally falls between f/2.8 and f/4. For a lens that has a maximum apertureof f/4, it's between f/8 and f/11.

 

[JimKasson]

copy and paste...

In general, this sweet spot is between two or three stops down from the maximum aperture. For example, for a lens that has a maximum aperture of f/1.4, the sweetspot normally falls between f/2.8 and f/4. For a lens that has a maximum apertureof f/4, it's between f/8 and f/11.

This is different from what you said here:

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www.dpreview.com

IMHO, this "rule" (whether your earlier 3-4 stop or the new 2-3 stop version) is so often not true that it's nearly worthless at best, and highly misleading at worst, like the old "focus 1/3 of the way into the part of the scene that you want sharp" rule.

Jim

 

[rospotte]

The sweet-spot of a given lense begins at least 2 stops down from wide open and covers a range of 3 to 4 stops for maximum sharpness. This is true for the majority of lenses made.

Now if you can point to a source that states differently I would like to read it.

 

[JimKasson]

The sweet-spot of a given lense begins at least 2 stops down from wide open and covers a range of 3 to 4 stops for maximum sharpness. This is true for the majority of lenses made.

Now if you can point to a source that states differently I would like to read it.

On axis testing that I've done with lots of lenses confirms that many don't conform to that so-called "rule". And the later designs see to conform to it less. I'm talking excellent lenses here, like the Fuji G lenses.

Jim

 

[rospotte]

You have not disproven the rule at all. I asked you to give me a source for your claims and all you have done is deflect from what is true for the majority of lenses made including the Fujifilm GF lenses.

 

[JimKasson]

You have not disproven the rule at all. I asked you to give me a source for your claims and all you have done is deflect from what is true for the majority of lenses made including the Fujifilm GF lenses.

Not the 110:

https://blog.kasson.com/the-last-word/focus-shift-loca-of-fuji-1102-on-gfx/

Not the 23:

https://blog.kasson.com/gfx-50s/focus-shift-loca-focus-stability-of-fuji-234-on-gfx/

Not the 120:

https://blog.kasson.com/the-last-word/fuji-1204-macro-at-12-on-gfx-loca-and-focus-shift/

Not the 250:

https://blog.kasson.com/gfx-50s/fuji-250-4-on-axis-sharpness-and-loca/

Not the 32-64:

https://blog.kasson.com/the-last-word/fuji-32-644-loca/

Jim

--
Posted as a regular forum member.
https://blog.kasson.com

 

[rospotte]

I mean a credible source. Show me one expert who agrees with you.

 

[JimKasson]

I mean a credible source.

Oh, my. You're a new kid on this MF block, it seems.

There is enough data in the links for you to reproduce the results for yourself. Give it a try and see if your findings are any different.

Jim

--
Posted as a regular forum member.
https://blog.kasson.com

 

[Chris Dodkin]

I mean a credible source. Show me one expert who agrees with you.

That's enough of that - personal attacks are not accepted here, posts deleted, and you'll not be coming back to the MF forum

--
Your time is limited, so don't waste it arguing about camera features - go out and capture memories - Oh, and size does matter - shoot MF

 

[Rick Knepper]

In general the sweet spot for any lens begins 3 or 4 notches from wide open.

I always heard it as 2 stops on the Canon forum. That might have been true for their big Whites which I've never used but Canon's WA lenses circa 2003 were more like 3-4 stops. But, I rented the Zeiss Otus 55/1.4 and realized that this old conventional wisdom doesn't have to be. With this lens, f1.4 was as sharp in the corners as my Canons were at f8. A lens doesn't have to incur diffraction to get the corners in focus. All it takes are customers with money and a company willing to service that market.

The Otus 55/1.4 performance is OK wide open, and spectacular stopped down to f/2.

Jim

The fact remains that the lens' performance wide open changed my perception of what is possible in lens design.

 

[Rick Knepper]

see with earlier post. Cheers.

I've looked at the Cambo Actus for GFX but I don't really know anything about the lenses being offered. Your description of the 110xl in conjunction with your pic got my curiosity up but the modifications are frankly worrisome. I'll have to look but I wonder if the Cambo has a lens board for these Schnieder lenses.

They do indeed make a plate with a #1 hole.

https://www.cambo.com/en/actus-series/actus-gfx-view-camera/

You want the ACB-1.

Jim

Thanks. I would have never recognized this description "copal-1 shutter or NK-1 aperture mount" as a Schneider characteristic.

 

[JimKasson]

see with earlier post. Cheers.

I've looked at the Cambo Actus for GFX but I don't really know anything about the lenses being offered. Your description of the 110xl in conjunction with your pic got my curiosity up but the modifications are frankly worrisome. I'll have to look but I wonder if the Cambo has a lens board for these Schnieder lenses.

They do indeed make a plate with a #1 hole.

https://www.cambo.com/en/actus-series/actus-gfx-view-camera/

You want the ACB-1.

Jim

Thanks. I would have never recognized this description "copal-1 shutter or NK-1 aperture mount" as a Schneider characteristic.

 

[Erik Kaffehr]

No focus stacking in this image, f22.

At f/22, does the lens you choose matter much wrt sharpness? Airy disk is 15.2 um for 555 nm light, and Sparrow distance is 12.4 nm, so the lens would have to have a lot of aberrations to override the diffraction. To put the 15 um number in perspective, the pixel pitch of the GFX 50x is 5.3 um.

Jim

So, Airy disk is 15.2 um in diameter, that is (15.2/2)^2 * Pi -> 181 um^2 according to my HP 32S. A pixel has 5.3x5.3 -> 29 um^2

So, we can fit 181 / 29 -> 6.2 pixels within the Airy disk. So, we have a 51 / 6 -> 8.5 MP camera. Is that right?

Best regards

Erik

 

[Erik Kaffehr]

The sweet-spot of a given lense begins at least 2 stops down from wide open and covers a range of 3 to 4 stops for maximum sharpness. This is true for the majority of lenses made.

Now if you can point to a source that states differently I would like to read it.

Hi,

It is simply the way that it is a balance of aberrations and diffraction.

Now diffraction cannot really be affected by lens design, it is a property of light and it is only affected by the aperture.

• So if you stop down diffraction increases.
• But when you stop down, aberrations go down.
• So the lens performs best at the aperture where aberrations low enough and diffraction has minimum effect.

An aberration free lens performs best at full aperture. The better a lens is corrected, the larger the optimum aperture may be.

There is no rule how much a lens needs to be stopped down. It is more about good lenses being aperture limited at say f/4. An f/4 lens doesn't need to be stopped down to f/4, but an f/1.4 lens needs to be stopped down three stops to reach f/4.

Best regards

Erik

 

[KEnrique]

I issue a challenge to produce an image sharper than this and with equal intensity of color. Gfx 50r mounted on Linhof 4x5 and Schneider Super Symmar 100xl. This lens is regarded as one of the finest in the world of large format photography. Image taken from a distance of six feet. Sorry but I am so astonished on what the gfx and the linhof combo can produce.

View attachment ad472304dc4c48b495f6d74196c04699.jpg
Gfx rocks!

Beautiful. Congrats!

 

[Rick Knepper]

see with earlier post. Cheers.

I've looked at the Cambo Actus for GFX but I don't really know anything about the lenses being offered. Your description of the 110xl in conjunction with your pic got my curiosity up but the modifications are frankly worrisome. I'll have to look but I wonder if the Cambo has a lens board for these Schnieder lenses.

They do indeed make a plate with a #1 hole.

https://www.cambo.com/en/actus-series/actus-gfx-view-camera/

You want the ACB-1.

Jim

Thanks. I would have never recognized this description "copal-1 shutter or NK-1 aperture mount" as a Schneider characteristic.

I can tell you’ve never spent much time with large format cameras. Wait till you see what you do to mount the lens to the lens board.

First off, I don't relish learning a whole new set of jargon. And, if it doesn't snap, screw or twist on easily, I'm out.