Nick Devlin 645D follow-up review on Luminous Landscape

claudefiddler · 11-16-2010, 08:55 PM

2010 Mini Medium Format Shoot-out

For those of you who remember the argument that testing wasn't too important and 10K should buy perfect quality check out the phase and pentax problems. I agree the problem is misalignment of the sensor.

Nick did a great review using a...wall for his critical test subject.

**blackcloudbrew** · 11-16-2010, 10:40 PM

This is a great review, very interesting.

**Canada_Rockies** · 11-16-2010, 10:59 PM

Very interesting link. Thank you!

drougge · 11-17-2010, 03:04 AM

Originally posted by claudefiddler

For those of you who remember the argument that testing wasn't too important and 10K should buy perfect quality check out the phase and pentax problems. I agree the problem is misalignment of the sensor.

I don't think he's saying the sensor is misaligned. I think he's saying the camera was not pointed straight at the wall.

ndevlin · 11-17-2010, 06:08 AM - **1 Like**

Originally posted by drougge

I don't think he's saying the sensor is misaligned. I think he's saying the camera was not pointed straight at the wall.

Thanks for the kind words, glad you enjoyed the write-up.

While I originally blamed sensor-angle, we have added an addendum to the article in which we posit that internal misalignment of the sensor or lens plane is a more likely culprit.

The more I think about this, the more likely I feel that this is the explanation, perhaps operating in conjunction with a failure to achieve perpendicularity to the wall (not a real concern in the real world).

On further reflection, I think it is likeliest that the lens is to blame, at least on my camera, since the fixed 75mm did just fine.

I'm going to reshoot this later this week, with a different camera along as well, just to mess around with this issue.

What this illustrates, however, is just how tight tolerances have to be in the digital world for 'ultimate' image quality to be realized.

Hopefully, however, our article also made it clear that the difference between "ultimate IQ" and what you actually get in a print is so minor to as to make little practical difference in most real-world applications.

Cheers!

- N.

claudefiddler · 11-17-2010, 07:21 PM

Nick

If the 75 was sharp in the corners....then the duck wasn't misalignment. Manual focus should have been a piece of cake. Trying to align the camera parallel to the wall is not an option a lot of the time in the real landscape world. As you know. I would have tried a focus bracket on a subject like this.

This is great info and a great pot stir.

Thanks

Claude

twitch · 11-17-2010, 07:38 PM

Here's a very interesting article that is relevent: https://www.lensrentals.com/news/2010.03.06/this-lens-is-soft-and-other-facts

Quote:

with a top quality wide-angle lens on a high resolution sensor, we can perceive a 20 micron difference [in alignment between the lens mount and the sensor], but the manufacturer probably can’t make the part more accurately than +/- 50 microns at a reasonable cost

ndevlin · 11-21-2010, 08:03 PM

Yes, that article is a must-read for anyone contemplating medium format. Kind of sobering...

Thanks again for the link.

- N.

paratom · 11-25-2010, 03:47 AM

Nick,
great review!
I am a Hy6 user and wondering if I might replace my Hy6 with the Pentax. I am a hobby shooter. The IQ of the Hy6 is great, but the AF not.
However a short fast (f3.5 or faster; I like the 110/2.0 Zeiss for my Hy6) telelens would be important to me. Is there any f2.8 or f3.5 AF Pentax lens in the 100-150mm range which you think should work fine on the Pentax? Have you tried?
Do you have any indication which lenses Pentax will bring over the next months/year?
It wouldnt help me to have a great camera body with good AF and then have to MF all the time. For that I could just keep my Sinar.

**Digitalis** · 11-25-2010, 05:35 AM

Originally posted by paratom

Is there any f2.8 or f3.5 AF Pentax lens in the 100-150mm range which you think should work fine on the Pentax? Have you tried?

Pentax does make a SMCP-645 FA150mm f/2.8 that is an excellent lens

paratom · 11-26-2010, 01:43 AM

OK-thank you. This might be the lens for ne.
I just dont know if the new 55m lens would be that usefull and if I should order it as a kit or the camera alone.
But then it would be nice to have one weatherproof lens for bad weather landscape shooting.
Overall I would see a potential kit like 35, 75, 150 + later a Macro and a TS lens.
Dont know yet how the 55 fits in there.

**Digitalis** · 11-26-2010, 02:01 AM

Originally posted by paratom

Overall I would see a potential kit like 35, 75, 150 + later a Macro and a TS lens.
Dont know yet how the 55 fits in there.

Don't forget pentax will be coming out with a 645 D-FA 25mm f/4 lens in the future which will give and effective focal length of 19.5mm in 35mm terms. From the mockup I have seen this lens will feature an internal filter holder not unlike pentax's super telephoto lens series.

ndevlin · 11-26-2010, 07:25 AM

Originally posted by paratom

[lang=de]Nick,
great review!
I am a Hy6 user and wondering if I might replace my Hy6 with the Pentax./lang]

To be honest, I would wait. switching MF systems is a very expensive proposition. If your IQ is satisfactory, then I don't see a compelling reason to switch.

The 645D's AF is good, but it's not 35mm-calbre in speed on the older lenses. Perhaps more importantly, I am still working through whether there are some focus precision issues.

The 645D might be the answer, but no need for you to be an early adopter.

- N.

paratom · 11-26-2010, 10:59 AM

Originally posted by ndevlin

To be honest, I would wait. switching MF systems is a very expensive proposition. If your IQ is satisfactory, then I don't see a compelling reason to switch.

The 645D's AF is good, but it's not 35mm-calbre in speed on the older lenses. Perhaps more importantly, I am still working through whether there are some focus precision issues.

The 645D might be the answer, but no need for you to be an early adopter.

- N.

Thanks. IQ is perfect with my Hy6 and Sinar back. Its more about size/ AF which is not so accurate and handling.

But you a re probably right that I shall wait - specially it concerns me if some people might have AF issues. I have learned that accurate focus is really critical to take advantage of the bigger sensor.

Thanks for keeping us updated about your experience with the 645D.
Tom

**Digitalis** · 11-26-2010, 04:08 PM

Originally posted by ndevlin

If your IQ is satisfactory, then I don't see a compelling reason to switch.

there is more to a camera than just it's IQ. While at the medium format level IQ is of paramount importance there are things such as interface,ergonomics/control layout, and functionality that are also important. getting the job done is important but if the tool you are using requires idiosyncratic workarounds or otherwise gets in the way, then I see no harm in assessing whether the particular tool can be replaced by one that may better suited to the photographer's requirements. The pentax 645D is undeniably a compelling addition to the realm of medium format DSLR cameras.

11-16-2010, 08:55 PM	#1
claudefiddler New Member Join Date: Oct 2010 Location: Crowley Lake, CA Posts: 22	Nick Devlin 645D follow-up review on Luminous Landscape 2010 Mini Medium Format Shoot-out For those of you who remember the argument that testing wasn't too important and 10K should buy perfect quality check out the phase and pentax problems. I agree the problem is misalignment of the sensor. Nick did a great review using a...wall for his critical test subject.

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11-16-2010, 10:40 PM	#2
blackcloudbrew Loyal Site Supporter Join Date: Mar 2009 Location: Cotati, California USA Photos: Gallery \| Albums Posts: 4,460	This is a great review, very interesting.

11-16-2010, 10:59 PM	#3
Canada_Rockies Loyal Site Supporter Join Date: Nov 2007 Location: Sparwood, BC, Canada Photos: Gallery \| Albums Posts: 12,385	Very interesting link. Thank you!

11-17-2010, 03:04 AM	#4
drougge Veteran Member Join Date: Jan 2010 Location: Malmö Photos: Gallery Posts: 787	Originally posted by claudefiddler For those of you who remember the argument that testing wasn't too important and 10K should buy perfect quality check out the phase and pentax problems. I agree the problem is misalignment of the sensor. I don't think he's saying the sensor is misaligned. I think he's saying the camera was not pointed straight at the wall.

11-17-2010, 06:08 AM - 1 Like	#5
ndevlin Senior Member Join Date: Oct 2010 Location: Toronto, Canada Posts: 132	Originally posted by drougge I don't think he's saying the sensor is misaligned. I think he's saying the camera was not pointed straight at the wall. Thanks for the kind words, glad you enjoyed the write-up. While I originally blamed sensor-angle, we have added an addendum to the article in which we posit that internal misalignment of the sensor or lens plane is a more likely culprit. The more I think about this, the more likely I feel that this is the explanation, perhaps operating in conjunction with a failure to achieve perpendicularity to the wall (not a real concern in the real world). On further reflection, I think it is likeliest that the lens is to blame, at least on my camera, since the fixed 75mm did just fine. I'm going to reshoot this later this week, with a different camera along as well, just to mess around with this issue. What this illustrates, however, is just how tight tolerances have to be in the digital world for 'ultimate' image quality to be realized. Hopefully, however, our article also made it clear that the difference between "ultimate IQ" and what you actually get in a print is so minor to as to make little practical difference in most real-world applications. Cheers! - N.

11-17-2010, 07:21 PM	#6
claudefiddler New Member Join Date: Oct 2010 Location: Crowley Lake, CA Posts: 22 Original Poster	Nick If the 75 was sharp in the corners....then the duck wasn't misalignment. Manual focus should have been a piece of cake. Trying to align the camera parallel to the wall is not an option a lot of the time in the real landscape world. As you know. I would have tried a focus bracket on a subject like this. This is great info and a great pot stir. Thanks Claude

11-17-2010, 07:38 PM	#7
twitch Veteran Member Join Date: Nov 2009 Posts: 4,571	Here's a very interesting article that is relevent: https://www.lensrentals.com/news/2010.03.06/this-lens-is-soft-and-other-facts Quote: with a top quality wide-angle lens on a high resolution sensor, we can perceive a 20 micron difference [in alignment between the lens mount and the sensor], but the manufacturer probably can’t make the part more accurately than +/- 50 microns at a reasonable cost

11-21-2010, 08:03 PM	#8
ndevlin Senior Member Join Date: Oct 2010 Location: Toronto, Canada Posts: 132	Yes, that article is a must-read for anyone contemplating medium format. Kind of sobering... Thanks again for the link. - N.

11-25-2010, 03:47 AM	#9
paratom Inactive Account Join Date: Nov 2010 Posts: 8	Nick, great review! I am a Hy6 user and wondering if I might replace my Hy6 with the Pentax. I am a hobby shooter. The IQ of the Hy6 is great, but the AF not. However a short fast (f3.5 or faster; I like the 110/2.0 Zeiss for my Hy6) telelens would be important to me. Is there any f2.8 or f3.5 AF Pentax lens in the 100-150mm range which you think should work fine on the Pentax? Have you tried? Do you have any indication which lenses Pentax will bring over the next months/year? It wouldnt help me to have a great camera body with good AF and then have to MF all the time. For that I could just keep my Sinar.

11-25-2010, 05:35 AM	#10
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by paratom Is there any f2.8 or f3.5 AF Pentax lens in the 100-150mm range which you think should work fine on the Pentax? Have you tried? Pentax does make a SMCP-645 FA150mm f/2.8 that is an excellent lens

11-26-2010, 01:43 AM	#11
paratom Inactive Account Join Date: Nov 2010 Posts: 8	OK-thank you. This might be the lens for ne. I just dont know if the new 55m lens would be that usefull and if I should order it as a kit or the camera alone. But then it would be nice to have one weatherproof lens for bad weather landscape shooting. Overall I would see a potential kit like 35, 75, 150 + later a Macro and a TS lens. Dont know yet how the 55 fits in there.

11-26-2010, 02:01 AM	#12
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by paratom Overall I would see a potential kit like 35, 75, 150 + later a Macro and a TS lens. Dont know yet how the 55 fits in there. Don't forget pentax will be coming out with a 645 D-FA 25mm f/4 lens in the future which will give and effective focal length of 19.5mm in 35mm terms. From the mockup I have seen this lens will feature an internal filter holder not unlike pentax's super telephoto lens series.

11-26-2010, 07:25 AM	#13
ndevlin Senior Member Join Date: Oct 2010 Location: Toronto, Canada Posts: 132	Originally posted by paratom [lang=de]Nick, great review! I am a Hy6 user and wondering if I might replace my Hy6 with the Pentax./lang] To be honest, I would wait. switching MF systems is a very expensive proposition. If your IQ is satisfactory, then I don't see a compelling reason to switch. The 645D's AF is good, but it's not 35mm-calbre in speed on the older lenses. Perhaps more importantly, I am still working through whether there are some focus precision issues. The 645D might be the answer, but no need for you to be an early adopter. - N.

11-26-2010, 10:59 AM	#14
paratom Inactive Account Join Date: Nov 2010 Posts: 8	Originally posted by ndevlin To be honest, I would wait. switching MF systems is a very expensive proposition. If your IQ is satisfactory, then I don't see a compelling reason to switch. The 645D's AF is good, but it's not 35mm-calbre in speed on the older lenses. Perhaps more importantly, I am still working through whether there are some focus precision issues. The 645D might be the answer, but no need for you to be an early adopter. - N. Thanks. IQ is perfect with my Hy6 and Sinar back. Its more about size/ AF which is not so accurate and handling. But you a re probably right that I shall wait - specially it concerns me if some people might have AF issues. I have learned that accurate focus is really critical to take advantage of the bigger sensor. Thanks for keeping us updated about your experience with the 645D. Tom

11-26-2010, 04:08 PM	#15
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	Originally posted by ndevlin If your IQ is satisfactory, then I don't see a compelling reason to switch. there is more to a camera than just it's IQ. While at the medium format level IQ is of paramount importance there are things such as interface,ergonomics/control layout, and functionality that are also important. getting the job done is important but if the tool you are using requires idiosyncratic workarounds or otherwise gets in the way, then I see no harm in assessing whether the particular tool can be replaced by one that may better suited to the photographer's requirements. The pentax 645D is undeniably a compelling addition to the realm of medium format DSLR cameras.