sdQH & fp with the 40mm Art f/1.4 - Kitchen Table Comparison

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

... According to Args and Ted, the adapter causes image quality degradation ...<>

Ted made no such simple statement, instead agreeing more with Cicala than Scottelly.

Cicala said:

... Although it doesn’t always work. Lloyd Chambers first reported years ago that with high-quality, wide-angle lenses you could detect very small misalignments in the camera-lens mount. Misalignment of 10 microns from side-to-side was enough to cause blur on the sides of the image.

What?!? BALDERDASH!

I can't agree with this statement: "Misalignment of 10 microns from side-to-side was enough to cause blur on the sides of the image."

What was that in reference to? A microscope?

Here Cicala tested a good few adapters:

https://www.lensrentals.com/blog/2013/09/there-is-no-free-lunch-episode-763-lens-adapters/

I won’t bore you with another 20 graphs that look pretty much like these. We tried Leica to NEX and Leica to Micro 4/3 adapters, Canon to NEX, etc. We tried different lenses on one adapter. It didn’t really matter. None of them would be acceptable for testing. Not one.

I’ll point out that we carry only name-brand, fairly expensive adapters, not eBay $29 adapters. All of them are tested frequently and used frequently and none of the ones I tested today had any problems. Still, not one of them would be acceptable for testing, so I guess I’m going to have to order those expensive lens mounts after all.

Maybe you should read the whole article.

There's no way . . . I repeat . . . NO WAY . . . that one tenth of a [millimeter] will make any noticeable difference to the image quality on an APS-C camera, let alone a full-frame camera. That statement seems totally absurd to me.

The resolution is so high on the Nikon D3x that the tiniest misalignment between lens mount and sensor and lens results in edge or corner blur. We’re talking 5-10 microns, an almost impossible manufacturing challenge. Why short focal lengths? Because the percentage error for any fixed alignment error is much larger.

https://diglloyd.com/blog/2009/20090802_1-UltraWideAlignment.html

Do you actually believe [Cicala's] statement Ted?

Yep, and no emotive response without credible references, such as yours, will change my mind.

Ted, neither of them seem to be taking into account that when tilting a lens all that happens is the angle of the focal plane changes slightly, something simple to adjust for by slightly changing the angle of the camera, and when shifting a lens even that doesn't happen. One milimeter of shift is like nothing. Most tilt shift adapters will shift up to ten milimeters! Then there would be a noticeabke difference, but shifting the center point of the image the lens projects across the sensor by just one tenth of a milimeter ir even by a whole milimeter is not going to have any significant affect on the image quality. If you can't see how that woukd be the case, then I don't know how else to help you understand, other than to get a tilt-shift adapter for a Sony E mount camera, and show you the resukts of shifting my Nikon 14-24mm f2.8 G over by 1 mm, and then shooting a comparison test shot. In fact, I've been planning to get just such an adapter, and I'll do this experiment for you, posting my resukts in the Adapted Lens Forum, so you can see for yourself. I'll even make shots with the lens shifter over 2 mm, so you can see the affect of a shift of twenty times what Roger Cicala claims is enough to make a lens "untestable."

Cicala knows his stuff and has all the test equipment and enough gear samples to prove/disprove anything he wants to.

Yeah, he surely does, which is why I can't understand why he would actually publish what he wrote.

Your lack of test equipment, test software, decent monitor, sample quantity and, dare I say, technical knowledge pales by comparison.

I guess I haven't earned your respect regarding my knowledge yet, and of course you're correct about my lack of test equipment. Still, I know enough to know that an image circle doesn't suddenly get blurry half a [millimeter] off the sensor.

I on the other hand know no such thing. Is there even one credible reference which backs up that statement? Anf why "suddenly" ??

If it did, then the corners of my SD Quattro H photos that I shot at 10 mm with my 8-16mm lens would all be quite blurry, wouldn't they?

A rhetorical question which needs no answer from me, sorry Scott.

xpatUSA wrote:

Scottelly wrote:

... According to Args and Ted, the adapter causes image quality degradation ...<>

Ted made no such simple statement, instead agreeing more with Cicala than Scottelly.

Cicala said:

... Although it doesn’t always work. Lloyd Chambers first reported years ago that with high-quality, wide-angle lenses you could detect very small misalignments in the camera-lens mount. Misalignment of 10 microns from side-to-side was enough to cause blur on the sides of the image. Since then a lot of other people have confirmed the same thing.

So when I hear people cavalierly talking about putting an adapter on their camera I tend to cringe. When a single camera-lens interface has enough variability to sometimes be visible, adding another large piece of metal with another mount interface seems a recipe for problems.

Don’t get me wrong. Generally, they’re acceptable or people wouldn’t use them ...

https://www.lensrentals.com/blog/2013/09/there-is-no-free-lunch-episode-763-lens-adapters/

So, please discuss the above without putting words in my mouth.

I would expect slight misalignment to show more the shorter the focal length of the lens. And the wider the aperture.

a 105mm f/2.5 lens should be quite forgiving.

Don

D Cox wrote:

xpatUSA wrote:

Scottelly wrote:

... According to Args and Ted, the adapter causes image quality degradation ...<>

Ted made no such simple statement, instead agreeing more with Cicala than Scottelly.

Cicala said:

... Although it doesn’t always work. Lloyd Chambers first reported years ago that with high-quality, wide-angle lenses you could detect very small misalignments in the camera-lens mount. Misalignment of 10 microns from side-to-side was enough to cause blur on the sides of the image. Since then a lot of other people have confirmed the same thing.

So when I hear people cavalierly talking about putting an adapter on their camera I tend to cringe. When a single camera-lens interface has enough variability to sometimes be visible, adding another large piece of metal with another mount interface seems a recipe for problems.

Don’t get me wrong. Generally, they’re acceptable or people wouldn’t use them ...

https://www.lensrentals.com/blog/2013/09/there-is-no-free-lunch-episode-763-lens-adapters/

So, please discuss the above without putting words in my mouth.

I would expect slight misalignment to show more the shorter the focal length of the lens. And the wider the aperture.

a 105mm f/2.5 lens should be quite forgiving.

Don

Thread title says a 40mm ƒ/1.4 lens

So, what have I learned from my two wee comparison threads?

1. DpReview's camera test of the sdQH used it's DNG output.

2.  The Quattro DNG images are inferior to those made using the X3F files and processed in SPP.

3. The DpReview test comparison of the sdQH and the fp proves the sdQH produces an obviously higher quality image, even using the poorer quality Quattro DNG files.

4. Lens adapters degrade image quality. SA mount Art lenses will deliver higher quality images with the sdQH compared with using the same lens,  with an adapter, on the fp.

5. The only comparisons that are acceptable are those that are factually sound and undertaken by qualified persons working under rigorous scientific conditions.

6. Points 2 , 3  & 4 above means a developed sdQH X3F image using a non-adapted SA mount lens will be of  significantly and obviously higher quality compared with an image from  the  fp with the same lens but with an adapter.

7.  Point 6 doesn't appear to hold water as the differences in two sets of images I produced from the sdQH and the fp are reasonably close in quality.

8.  Point 7 above isn't creditable because I've fallen foul of point 5.

Best, Steve

josepmg wrote:

furtle wrote:

So, what have I learned from my two wee comparison threads?

1. DpReview's camera test of the sdQH used it's DNG output.

The DpReview camera test of the sdQH has a DNG output but also an X3F (recommended).

But viewing the X3F is not available in the famous DPR Image Quality Camera Comparison Tool, only the DNG.

2. The Quattro DNG images are inferior to those made using the X3F files and processed in SPP.

3. The DpReview test comparison of the sdQH and the fp proves the sdQH produces an obviously higher quality image, even using the poorer quality Quattro DNG files.

4. Lens adapters degrade image quality. SA mount Art lenses will deliver higher quality images with the sdQH compared with using the same lens, with an adapter, on the fp.

5. The only comparisons that are acceptable are those that are factually sound and undertaken by qualified persons working under rigorous scientific conditions.

Not necessarily.

Agreed, but points 7 and 8 below reveal that Steve was being sarcastic about 3-6.

6. Points 2 , 3 & 4 above means a developed sdQH X3F image using a non-adapted SA mount lens will be of significantly and obviously higher quality compared with an image from the fp with the same lens but with an adapter.

Too many variables influence quality to obsess over this possibility.

Agreed.

7. Point 6 doesn't appear to hold water as the differences in two sets of images I produced from the sdQH and the fp are reasonably close in quality.

8. Point 7 above isn't creditable because I've fallen foul of point 5.

Best, Steve

back at you.

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

... According to Args and Ted, the adapter causes image quality degradation ...<>

Ted made no such simple statement, instead agreeing more with Cicala than Scottelly.

Cicala said:

... Although it doesn’t always work. Lloyd Chambers first reported years ago that with high-quality, wide-angle lenses you could detect very small misalignments in the camera-lens mount. Misalignment of 10 microns from side-to-side was enough to cause blur on the sides of the image.

What?!? BALDERDASH!

I can't agree with this statement: "Misalignment of 10 microns from side-to-side was enough to cause blur on the sides of the image."

What was that in reference to? A microscope?

Here Cicala tested a good few adapters:

https://www.lensrentals.com/blog/2013/09/there-is-no-free-lunch-episode-763-lens-adapters/

I won’t bore you with another 20 graphs that look pretty much like these. We tried Leica to NEX and Leica to Micro 4/3 adapters, Canon to NEX, etc. We tried different lenses on one adapter. It didn’t really matter. None of them would be acceptable for testing. Not one.

I’ll point out that we carry only name-brand, fairly expensive adapters, not eBay $29 adapters. All of them are tested frequently and used frequently and none of the ones I tested today had any problems. Still, not one of them would be acceptable for testing, so I guess I’m going to have to order those expensive lens mounts after all.

Maybe you should read the whole article.

There's no way . . . I repeat . . . NO WAY . . . that one tenth of a [millimeter] will make any noticeable difference to the image quality on an APS-C camera, let alone a full-frame camera. That statement seems totally absurd to me.

The resolution is so high on the Nikon D3x that the tiniest misalignment between lens mount and sensor and lens results in edge or corner blur. We’re talking 5-10 microns, an almost impossible manufacturing challenge. Why short focal lengths? Because the percentage error for any fixed alignment error is much larger.

https://diglloyd.com/blog/2009/20090802_1-UltraWideAlignment.html

Do you actually believe [Cicala's] statement Ted?

Yep, and no emotive response without credible references, such as yours, will change my mind.

Ted, neither of them seem to be taking into account that when tilting a lens all that happens is the angle of the focal plane changes slightly, something simple to adjust for by slightly changing the angle of the camera, and when shifting a lens even that doesn't happen. One milimeter of shift is like nothing. Most tilt shift adapters will shift up to ten milimeters! Then there would be a noticeabke difference, but shifting the center point of the image the lens projects across the sensor by just one tenth of a milimeter ir even by a whole milimeter is not going to have any significant affect on the image quality. If you can't see how that woukd be the case, then I don't know how else to help you understand, other than to get a tilt-shift adapter for a Sony E mount camera, and show you the resukts of shifting my Nikon 14-24mm f2.8 G over by 1 mm, and then shooting a comparison test shot. In fact, I've been planning to get just such an adapter, and I'll do this experiment for you, posting my resukts in the Adapted Lens Forum, so you can see for yourself. I'll even make shots with the lens shifter over 2 mm, so you can see the affect of a shift of twenty times what Roger Cicala claims is enough to make a lens "untestable."

Cicala knows his stuff and has all the test equipment and enough gear samples to prove/disprove anything he wants to.

Yeah, he surely does, which is why I can't understand why he would actually publish what he wrote.

Your lack of test equipment, test software, decent monitor, sample quantity and, dare I say, technical knowledge pales by comparison.

I guess I haven't earned your respect regarding my knowledge yet, and of course you're correct about my lack of test equipment. Still, I know enough to know that an image circle doesn't suddenly get blurry half a [millimeter] off the sensor.

I on the other hand know no such thing.

I think you probably do, but are forgetting, or just refusing to acknowledge it for some reason, because you've surely seen the corners photos people have posted here from their APS-C lenses that they used on their SD Quattro H - mine, for instance.

Is there even one credible reference which backs up that statement? Anf why "suddenly" ??

If it did, then the corners of my SD Quattro H photos that I shot at 10 mm with my 8-16mm lens would all be quite blurry, wouldn't they?

A rhetorical question which needs no answer from me, sorry Scott.

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

... According to Args and Ted, the adapter causes image quality degradation ...<>

Ted made no such simple statement, instead agreeing more with Cicala than Scottelly.

Cicala said:

... Although it doesn’t always work. Lloyd Chambers first reported years ago that with high-quality, wide-angle lenses you could detect very small misalignments in the camera-lens mount. Misalignment of 10 microns from side-to-side was enough to cause blur on the sides of the image.

What?!? BALDERDASH!

I can't agree with this statement: "Misalignment of 10 microns from side-to-side was enough to cause blur on the sides of the image."

What was that in reference to? A microscope?

Here Cicala tested a good few adapters:

https://www.lensrentals.com/blog/2013/09/there-is-no-free-lunch-episode-763-lens-adapters/

I won’t bore you with another 20 graphs that look pretty much like these. We tried Leica to NEX and Leica to Micro 4/3 adapters, Canon to NEX, etc. We tried different lenses on one adapter. It didn’t really matter. None of them would be acceptable for testing. Not one.

I’ll point out that we carry only name-brand, fairly expensive adapters, not eBay $29 adapters. All of them are tested frequently and used frequently and none of the ones I tested today had any problems. Still, not one of them would be acceptable for testing, so I guess I’m going to have to order those expensive lens mounts after all.

Maybe you should read the whole article.

There's no way . . . I repeat . . . NO WAY . . . that one tenth of a [millimeter] will make any noticeable difference to the image quality on an APS-C camera, let alone a full-frame camera. That statement seems totally absurd to me.

The resolution is so high on the Nikon D3x that the tiniest misalignment between lens mount and sensor and lens results in edge or corner blur. We’re talking 5-10 microns, an almost impossible manufacturing challenge. Why short focal lengths? Because the percentage error for any fixed alignment error is much larger.

https://diglloyd.com/blog/2009/20090802_1-UltraWideAlignment.html

Do you actually believe [Cicala's] statement Ted?

Yep, and no emotive response without credible references, such as yours, will change my mind.

Ted, neither of them seem to be taking into account that when tilting a lens all that happens is the angle of the focal plane changes slightly, something simple to adjust for by slightly changing the angle of the camera, and when shifting a lens even that doesn't happen. One milimeter of shift is like nothing. Most tilt shift adapters will shift up to ten milimeters! Then there would be a noticeabke difference, but shifting the center point of the image the lens projects across the sensor by just one tenth of a milimeter ir even by a whole milimeter is not going to have any significant affect on the image quality. If you can't see how that woukd be the case, then I don't know how else to help you understand, other than to get a tilt-shift adapter for a Sony E mount camera, and show you the resukts of shifting my Nikon 14-24mm f2.8 G over by 1 mm, and then shooting a comparison test shot. In fact, I've been planning to get just such an adapter, and I'll do this experiment for you, posting my resukts in the Adapted Lens Forum, so you can see for yourself. I'll even make shots with the lens shifter over 2 mm, so you can see the affect of a shift of twenty times what Roger Cicala claims is enough to make a lens "untestable."

Cicala knows his stuff and has all the test equipment and enough gear samples to prove/disprove anything he wants to.

Yeah, he surely does, which is why I can't understand why he would actually publish what he wrote.

Your lack of test equipment, test software, decent monitor, sample quantity and, dare I say, technical knowledge pales by comparison.

I guess I haven't earned your respect regarding my knowledge yet, and of course you're correct about my lack of test equipment. Still, I know enough to know that an image circle doesn't suddenly get blurry half a [millimeter] off the sensor.

I on the other hand know no such thing.

I think you probably do, but are forgetting, or just refusing to acknowledge it for some reason ...

I resent those remarks.

... because you've surely seen the corners photos people have posted here from their APS-C lenses that they used on their [sd] Quattro H - mine, for instance.

I have never been interested in any discussion re: mounting APS-C lenses on an sd Quattro H. Any images not showing or indeed showing vignetting caused thereby have, as you say, long faded from my memory ...

Is there even one credible reference which backs up "I know enough to know that an image circle doesn't suddenly get blurry half a [millimeter] off the sensor" statement? And why "suddenly" ??

I take it that a response is not forthcoming. No need to reply to the rhetoric which has already done it's work ...

TN Args wrote:

josepmg wrote:

furtle wrote:

So, what have I learned from my two wee comparison threads?

1. DpReview's camera test of the sdQH used it's DNG output.

The DpReview camera test of the sdQH has a DNG output but also an X3F (recommended).

But viewing the X3F is not available in the famous DPR Image Quality Camera Comparison Tool, only the DNG.

2. The Quattro DNG images are inferior to those made using the X3F files and processed in SPP.

3. The DpReview test comparison of the sdQH and the fp proves the sdQH produces an obviously higher quality image, even using the poorer quality Quattro DNG files.

4. Lens adapters degrade image quality. SA mount Art lenses will deliver higher quality images with the sdQH compared with using the same lens, with an adapter, on the fp.

5. The only comparisons that are acceptable are those that are factually sound and undertaken by qualified persons working under rigorous scientific conditions.

Not necessarily.

Agreed, but points 7 and 8 below reveal that Steve was being sarcastic about 3-6.

Nope, no sarcasm  I'm just summarising my understanding of points made in the two comparison threads I started.

6. Points 2 , 3 & 4 above means a developed sdQH X3F image using a non-adapted SA mount lens will be of significantly and obviously higher quality compared with an image from the fp with the same lens but with an adapter.

Too many variables influence quality to obsess over this possibility.

Agreed.

7. Point 6 doesn't appear to hold water as the differences in two sets of images I produced from the sdQH and the fp are reasonably close in quality.

8. Point 7 above isn't creditable because I've fallen foul of point 5.

Best, Steve

back at you.

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

... According to Args and Ted, the adapter causes image quality degradation ...<>

Ted made no such simple statement, instead agreeing more with Cicala than Scottelly.

Cicala said:

... Although it doesn’t always work. Lloyd Chambers first reported years ago that with high-quality, wide-angle lenses you could detect very small misalignments in the camera-lens mount. Misalignment of 10 microns from side-to-side was enough to cause blur on the sides of the image.

What?!? BALDERDASH!

I can't agree with this statement: "Misalignment of 10 microns from side-to-side was enough to cause blur on the sides of the image."

What was that in reference to? A microscope?

Here Cicala tested a good few adapters:

https://www.lensrentals.com/blog/2013/09/there-is-no-free-lunch-episode-763-lens-adapters/

I won’t bore you with another 20 graphs that look pretty much like these. We tried Leica to NEX and Leica to Micro 4/3 adapters, Canon to NEX, etc. We tried different lenses on one adapter. It didn’t really matter. None of them would be acceptable for testing. Not one.

I’ll point out that we carry only name-brand, fairly expensive adapters, not eBay $29 adapters. All of them are tested frequently and used frequently and none of the ones I tested today had any problems. Still, not one of them would be acceptable for testing, so I guess I’m going to have to order those expensive lens mounts after all.

Maybe you should read the whole article.

There's no way . . . I repeat . . . NO WAY . . . that one tenth of a [millimeter] will make any noticeable difference to the image quality on an APS-C camera, let alone a full-frame camera. That statement seems totally absurd to me.

The resolution is so high on the Nikon D3x that the tiniest misalignment between lens mount and sensor and lens results in edge or corner blur. We’re talking 5-10 microns, an almost impossible manufacturing challenge. Why short focal lengths? Because the percentage error for any fixed alignment error is much larger.

https://diglloyd.com/blog/2009/20090802_1-UltraWideAlignment.html

Do you actually believe [Cicala's] statement Ted?

Yep, and no emotive response without credible references, such as yours, will change my mind.

Ted, neither of them seem to be taking into account that when tilting a lens all that happens is the angle of the focal plane changes slightly, something simple to adjust for by slightly changing the angle of the camera, and when shifting a lens even that doesn't happen. One milimeter of shift is like nothing. Most tilt shift adapters will shift up to ten milimeters! Then there would be a noticeabke difference, but shifting the center point of the image the lens projects across the sensor by just one tenth of a milimeter ir even by a whole milimeter is not going to have any significant affect on the image quality. If you can't see how that woukd be the case, then I don't know how else to help you understand, other than to get a tilt-shift adapter for a Sony E mount camera, and show you the resukts of shifting my Nikon 14-24mm f2.8 G over by 1 mm, and then shooting a comparison test shot. In fact, I've been planning to get just such an adapter, and I'll do this experiment for you, posting my resukts in the Adapted Lens Forum, so you can see for yourself. I'll even make shots with the lens shifter over 2 mm, so you can see the affect of a shift of twenty times what Roger Cicala claims is enough to make a lens "untestable."

Cicala knows his stuff and has all the test equipment and enough gear samples to prove/disprove anything he wants to.

Yeah, he surely does, which is why I can't understand why he would actually publish what he wrote.

Your lack of test equipment, test software, decent monitor, sample quantity and, dare I say, technical knowledge pales by comparison.

I guess I haven't earned your respect regarding my knowledge yet, and of course you're correct about my lack of test equipment. Still, I know enough to know that an image circle doesn't suddenly get blurry half a [millimeter] off the sensor.

I on the other hand know no such thing.

I think you probably do, but are forgetting, or just refusing to acknowledge it for some reason ...

I resent those remarks.

... because you've surely seen the corners photos people have posted here from their APS-C lenses that they used on their [sd] Quattro H - mine, for instance.

I have never been interested in any discussion re: mounting APS-C lenses on an sd Quattro H. Any images not showing or indeed showing vignetting caused thereby have, as you say, long faded from my memory ...

Is there even one credible reference which backs up "I know enough to know that an image circle doesn't suddenly get blurry half a [millimeter] off the sensor" statement? And why "suddenly" ??

Suddenly, as in over a small distance from the sensor (as in suddenly as in it was not blurry, and then, as the lens moves ever so slightly to the side it gets suddenly blurry).

Here is a link that shows full resolution thotos from my ultra-wide-angle lens, but I shot them with my SD Quattro H Ted, so the edges are at least a full milimeter outside of the SPS-C dimensions, so each edge shows the way the edge of an APS-C sencor would have captured that edge of the image if an adapter was used that was made wrong, and the lens is a milimeter or two to the right or left of where it should be (like ten times what Roger Cicala and that other guy claim is so bad that it causes significant blur).

https://www.dpreview.com/forums/post/62634750

There are several other posts in that thread, in which I posted other sample photos from that camera and lens combination.

Needless to say, one tenth of a milimeter is an incredibly small amount of shift, and these photos show that even a much larger shift would hardly make any difference to the image quality at the edges of an APS-C sensor.

I take it that a response is not forthcoming. No need to reply to the rhetoric which has already done it's work ...

furtle wrote:

So, what have I learned from my two wee comparison threads?

1. DpReview's camera test of the sdQH used it's DNG output.

2. The Quattro DNG images are inferior to those made using the X3F files and processed in SPP.

3. The DpReview test comparison of the sdQH and the fp proves the sdQH produces an obviously higher quality image, even using the poorer quality Quattro DNG files.

4. Lens adapters degrade image quality. SA mount Art lenses will deliver higher quality images with the sdQH compared with using the same lens, with an adapter, on the fp.

5. The only comparisons that are acceptable are those that are factually sound and undertaken by qualified persons working under rigorous scientific conditions.

6. Points 2 , 3 & 4 above means a developed sdQH X3F image using a non-adapted SA mount lens will be of significantly and obviously higher quality compared with an image from the fp with the same lens but with an adapter.

7. Point 6 doesn't appear to hold water as the differences in two sets of images I produced from the sdQH and the fp are reasonably close in quality.

8. Point 7 above isn't creditable because I've fallen foul of point 5.

Best, Steve

But point 27 says . . .

😲

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Is there even one credible reference which backs up "I know enough to know that an image circle doesn't suddenly get blurry half a [millimeter] off the sensor" statement? And why "suddenly" ??

Suddenly, as in over a small distance from the sensor (as in suddenly as in it was not blurry, and then, as the lens moves ever so slightly to the side it gets suddenly blurry). <>

Image blur does not work like that, Scott.

If you can not agree, please provide a credible reference that upholds your claim.

[edit]

I think you are confusing "shift" with Cicala's tests which are to do with differences in distance from the lens flange to the sensor.

I do agree that a shift of lens position caused by an adapter will make no difference provided that all four faces are parallel.

However, I am assuming that Cicala's test setup ensures that the target is parallel with the sensor. Which leaves tilt (adapter faces not parallel) as a possible cause of varying focus across an image - as indeed shown in his test results.

No need to mention tilt lenses in support of your claim, I am not discussing their usage in this context.

[/edit]

... I bet that Iain is just loving this exchange ...

… Ted: Sorry. Been out taking pictures….

... good one, Iain! ...

josepmg wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Is there even one credible reference which backs up "I know enough to know that an image circle doesn't suddenly get blurry half a [millimeter] off the sensor" statement? And why "suddenly" ??

Suddenly, as in over a small distance from the sensor (as in suddenly as in it was not blurry, and then, as the lens moves ever so slightly to the side it gets suddenly blurry). <>

Image blur does not work like that, Scott.

If you can not agree, please provide a credible reference that upholds your claim.

[edit]

I think you are confusing "shift" with Cicala's tests which are to do with differences in distance from the lens flange to the sensor.

I do agree that a shift of lens position caused by an adapter will make no difference provided that all four faces are parallel.

However, I am assuming that Cicala's test setup ensures that the target is parallel with the sensor. Which leaves tilt (adapter faces not parallel) as a possible cause of varying focus across an image - as indeed shown in his test results.

Could it be that if we take care that two of the three elements (camera, lens and adapter) are perfectly parallel, we will always be able to say that the fault of the tilt is the third element, regardless of which one it is?

Yes indeed, José.

Because we are talking about adapters, so far I have assumed a perfect lens flange and a perfect lens mount on a perfect camera. Therefore, my posts have assumed that the adapter is your third element.

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Is there even one credible reference which backs up "I know enough to know that an image circle doesn't suddenly get blurry half a [millimeter] off the sensor" statement? And why "suddenly" ??

Suddenly, as in over a small distance from the sensor (as in suddenly as in it was not blurry, and then, as the lens moves ever so slightly to the side it gets suddenly blurry). <>

Image blur does not work like that, Scott.

If you can not agree, please provide a credible reference that upholds your claim.

[edit]

I think you are confusing "shift" with Cicala's tests which are to do with differences in distance from the lens flange to the sensor.

Ted, in this thread I quoted: I can't agree with this statement: "Misalignment of 10 microns from side-to-side was enough to cause blur on the sides of the image."

See where it says, ". . . from side-to-side . . ." Ted?

https://www.dpreview.com/forums/post/66947476

I do agree that a shift of lens position caused by an adapter will make no difference provided that all four faces are parallel.

Thank you for saying that, and I'm glad. That shows to me that you don't disagree with what seemed obvious to me by the many examples I have seen in the past from photos shot with tilt-shift adapters.

However, I am assuming that Cicala's test setup ensures that the target is parallel with the sensor. Which leaves tilt (adapter faces not parallel) as a possible cause of varying focus across an image - as indeed shown in his test results.

That could indeed happen Ted, but a tilt of a few microns further away or closer to the sensor at one side of a mount that is like forty or fifty milimeters in diameter works out to an incredibly insignificant tilt. With a tilt-shift set-up, such as a bellows camera (4x5 large format, for instance) the maximum tilt is often as much as 45 degrees. I believe five degrees is enough to significantly change the focal plane, so the perfectly focused plane would be changed enough to cause significant blur, when using wide apertures on close subjects, even with a wide-angle lens. A few microns over 45mm is not five degrees though. In fact, it's not even one degree, and one degree is almost imperceptible, unless you're shooting macro shots of subjects less than one foot from the lens, and using a wide aperture lens (i.e. f1.4 or f2.8) wide open, or very close to wide open.

Imagine tilting the camera by one degree. That'd be pretty difficult to measure, huh? How many times have you considered/wondered if your plane of focus matched a wall you were focusing on? I have many times. I never imagined I would get my camera's sensor within one degree of being parallel to the wall. I have done the same with paintings and old photo prints several times. I doubt my estimates were accurate within one degree, but that isn't generally necessary, because I would just focus on one corner, shoot a photo, and check the focus on the far corner. Then I'd make an adjustment if necessary. I don't know why Roger Cicala can't or won't do the same, when testing his lens and adapter combinations.

No need to mention tilt lenses in support of your claim, I am not discussing their usage in this context.

[/edit]

... I bet that Iain is just loving this exchange ...

-- hide signature --

what you got is not what you saw ...

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

Is there even one credible reference which backs up "I know enough to know that an image circle doesn't suddenly get blurry half a [millimeter] off the sensor" statement? And why "suddenly" ??

Suddenly, as in over a small distance from the sensor (as in suddenly as in it was not blurry, and then, as the lens moves ever so slightly to the side it gets suddenly blurry). <>

Image blur does not work like that, Scott.

If you can not agree, please provide a credible reference that upholds your claim.

[edit]

I think you are confusing "shift" with Cicala's tests which are to do with differences in distance from the lens flange to the sensor.

Ted, in this thread I quoted: I can't agree with this statement: "Misalignment of 10 microns from side-to-side was enough to cause blur on the sides of the image."

See where it says, ". . . from side-to-side . . ." Ted?

https://www.dpreview.com/forums/post/66947476

I do agree that a shift of lens position caused by an adapter will make no difference provided that all four faces are parallel.

Thank you for saying that, and I'm glad. That shows to me that you don't disagree with what seemed obvious to me by the many examples I have seen in the past from photos shot with tilt-shift adapters.

However, I am assuming that Cicala's test setup ensures that the target is parallel with the sensor. Which leaves tilt (adapter faces not parallel) as a possible cause of varying focus across an image - as indeed shown in his test results.

That could indeed happen Ted, but a tilt of a few microns further away or closer to the sensor at one side of a mount that is like forty or fifty milimeters in diameter works out to an incredibly insignificant tilt. With a tilt-shift set-up, such as a bellows camera (4x5 large format, for instance) the maximum tilt is often as much as 45 degrees. I believe five degrees is enough to significantly change the focal plane, so the perfectly focused plane would be changed enough to cause significant blur, when using wide apertures on close subjects, even with a wide-angle lens. A few microns over 45mm is not five degrees though. In fact, it's not even one degree, and one degree is almost imperceptible, unless you're shooting macro shots of subjects less than one foot from the lens, and using a wide aperture lens (i.e. f1.4 or f2.8) wide open, or very close to wide open.

Imagine tilting the camera by one degree. That'd be pretty difficult to measure, huh? How many times have you considered/wondered if your plane of focus matched a wall you were focusing on? I have many times. I never imagined I would get my camera's sensor within one degree of being parallel to the wall. I have done the same with paintings and old photo prints several times. I doubt my estimates were accurate within one degree, but that isn't generally necessary, because I would just focus on one corner, shoot a photo, and check the focus on the far corner. Then I'd make an adjustment if necessary. I don't know why Roger Cicala can't or won't do the same, when testing his lens and adapter combinations.

I'm done on this subject, Scott. Roger Cicala is a member of DPR. I suggest that you express your concerns directly to him.