We audiophiles are not the only hobbyists with issues......

[bluesman]

I came across a fascinating article posted on the photography site on which I'm a long time participant (photo.net) . It's not unlike the AS community - I've always enjoyed my interaction with the many useful, educational, and entertaining participants and even some of the usual assortment of issue-driven people.  I think this was posted as a bridge between humor and the quandry of finding and using objective testing to judge the quality of equipment.  I suspect it will stir up a bit of laughter, a bit of interest, and more than a bit of controversy.  There might even be similar "tests" in use by audiophiles.

 

Click HERE to learn about "the brick wall test".

 

[PS:  Yes, it was an April Fool's post - but not everyone posting in response to it seems to have known that.  So there are some responses that could just as easily have been found right here 😉 ]

[AudioDoctor]

I have to do this with my iPhone now to make sure I am getting the correct color balance when I take pictures of my food and my cat.

[yamamoto2002]

I use ColorChecker Classic instead of brick wall and Matlab Image Processing Toolbox measureColor() and imapplymatrix() to correct color appearance of photos, when it is necessary.

 

To get lens distortion parameters and undistort photos, I take multiple images of DIY A4 size Checkerboard and Single Camera Calibrator app of Matlab Computer Vision Toolbox. There is OpenCV alternative and it is free.

[accwai]

On 4/26/2021 at 5:51 AM, yamamoto2002 said:

I use ColorChecker Classic instead of brick wall and Matlab Image Processing Toolbox measureColor() and imapplymatrix() to correct color appearance of photos, when it is necessary.

 

The freely available X-Rite ColorChecker Camera Calibration is supposed to be able to generate DNG/ICC camera profiles from many ColorChecker variants. Wouldn't that do? Back in the DNG Profile Manager days, one can give it two calibration photos at different light source color temperature and it's said that Lightroom can then interpolate across the whole input image color temperature range based on the resulting DNG profile. The same should be in the current generation.

 

Quote

To get lens distortion parameters and undistort photos, I take multiple images of DIY A4 size Checkerboard and Single Camera Calibrator app of Matlab Computer Vision Toolbox. There is OpenCV alternative and it is free.

 

Wouldn't lens distortion depend on focus distance? PTLens recommends at least 25ft from a building facade with perfect straight lines. And for zooms, 10-12 images with denser distribution on the short side where distortion characteristic changes more quickly.

 

By the way, any before/after demo photos of your process?

[bluesman]

So no one has a “brick wall test” for SQ???

[semente]

A REW sweep?

[accwai]

7 hours ago, bluesman said:

So no one has a “brick wall test” for SQ???

 

How about Radiohead's Packt Like Sardines In a Crushd Tin Box? By the way, how's the brick wall test below? Is it acceptable by stringent standard of the internet experts?

 

[bluesman]

40 minutes ago, accwai said:

By the way, how's the brick wall test below? Is it acceptable by stringent standard of the internet experts?

 

 

Search me!  I have ebnough trouble finding objective audio measurements 😉

[yamamoto2002]

10 hours ago, accwai said:

The freely available X-Rite ColorChecker Camera Calibration is supposed to be able to generate DNG/ICC camera profiles from many ColorChecker variants. Wouldn't that do? Back in the DNG Profile Manager days, one can give it two calibration photos at different light source color temperature and it's said that Lightroom can then interpolate across the whole input image color temperature range based on the resulting DNG profile. The same should be in the current generation.

 

Matlab solution works well for me. I think X-Rite ColorChecker app is not easy to use, ColorChecker chart detection function sometimes does not work for no reason.😀

 

10 hours ago, accwai said:

Wouldn't lens distortion depend on focus distance? PTLens recommends at least 25ft from a building facade with perfect straight lines. And for zooms, 10-12 images with denser distribution on the short side where distortion characteristic changes more quickly.

 

Yes. I fixed the focal length using permacel tape. Also camera parameter changes when lens is detached and re-attached (optical center is shifted by several dozen pixels). I don't use zoom lens

[sphinxsix]

1 hour ago, accwai said:

By the way, how's the brick wall test below? Is it acceptable by stringent standard of the internet experts?

 

 

IMO a more proper one in case of a music loving photographer 

 

[accwai]

On 4/27/2021 at 5:12 PM, yamamoto2002 said:

Matlab solution works well for me. I think X-Rite ColorChecker app is not easy to use, ColorChecker chart detection function sometimes does not work for no reason.😀

 

Looks like the X-Rite app is quite finicky about data in the patches. And when it runs into problems, it just tells you something generic like capture size not big enough. The chart function in the Adobe DNG Profile Editor has much more specific error message, down to which patch is causing problem. So running the captures through that could provide some insight. How easy/painful the process is probably depends on the color engine in the specific camera. The before/after DNG profiling below is from a phone:

 

 

 

DNG file from the phone is pretty much useless without camera profiling. But the amount of twisting the profile does is quite significant. So even with it, strange behavior could be lurking in the process somewhere. We will see...

[NoNaim]

On 4/25/2021 at 9:57 PM, bluesman said:

There might even be similar "tests" in use by audiophiles.

 

If only there was🤣

 

It's the first test done on a new lens to arrive here... test at each aperture to see if there are any major decentring problems with the lens. Courier jugglers often drop parcels so getting a centred lens can be a problem. And that's before manufacturing issues. There are other more stringent tests done but when buying a £1k-£4k lens you want it to be right. And it doesn't take long... unlike audiophile A/B 😂

[accwai]

On 5/26/2021 at 6:07 AM, NoNaim said:

There are other more stringent tests done but when buying a £1k-£4k lens you want it to be right.

 

What kind of stringent tests need to be done on those lenses? Actually I'm really curious what kind of lens could be worth that much. Any example of the kind of images those lenses would provide in real use?

[NoNaim]

26 minutes ago, accwai said:

 

What kind of stringent tests need to be done on those lenses? Actually I'm really curious what kind of lens could be worth that much. Any example of the kind of images those lenses would provide in real use?

 

This web link has one of the better real world tests rather than shooting a test / target from a few feet. Some lenses may perform very well close up but not so well at distance. The other issues is Field Curvature of a lens. In other words, focus across the lens may not be even as you move further to the edge of the Frame.

 

I shoot with Sony A9 & Leica Q-P cameras at the moment and use Zeiss & Sony GM lenses. Most of these vary from about £1k - £12k for the longer lenses. A good average is probably around the £2.5k. The longer prime lenses used for sports and wildlife photography will set you back between £8k - £12k while a Zeiss cinematic zoom lens can cost £15k-£20k. And even they aren't the most expensive 🤣

 

Thankfully most lenses I need normally top out at the £4K mark.

 

 

[accwai]

22 hours ago, NoNaim said:

[...] Zeiss & Sony GM lenses. Most of these vary from about £1k - £12k for the longer lenses. [...] Thankfully most lenses I need normally top out at the £4K mark.

 

I'm quite curious the kind of image that needs £2.5k-£4K lens to produce. Any examples to share?

[yamamoto2002]

I'm also curious, large aperture prime lenses always disappoint me for poor corner sharpness even on F5.6 ～ F8.

For example, my Nikon AF-S 24mm F1.8 is better than AF-S 24mm F1.4
 

And wide aperture of lenses cannot be used anyway.  It is waste of sensor resolution

 

 

[NoNaim]

1 hour ago, accwai said:

 

I'm quite curious the kind of image that needs £2.5k-£4K lens to produce. Any examples to share?

 

All sorts. Think of time is money. If I buy a cheaper lenses that are either not very sharp, have aberrations that have to be corrected or poor colouring then they all have to be corrected in post. If I buy an expensive lens that has no such issues and I can rely on it's output 100% (excluding photographer errors) then I spend more time shooting and creating illustrations from the images and less time correcting problems caused by a poor lens. Over weeks, months and years... than can be quite a saving.

 

I mainly shoot outdoor adventure / activities and stock photography. It's a full time job so a lens of that amount has generally paid its way after a month. I don't update my website as often as I should... it's not really used to gain work as such but is handy to deliver jobs I get. Link

 

33 minutes ago, yamamoto2002 said:

I'm also curious, large aperture prime lenses always disappoint me for poor corner sharpness even on F5.6 ～ F8.

For example, my Nikon AF-S 24mm F1.8 is better than AF-S 24mm F1.4
 

And wide aperture of lenses cannot be used anyway.  It is waste of sensor resolution

 

 

 

The Sony 24gm 1.4 is pretty much sharp to the edge at 1.4. Incredible lens. The Zeiss 135 2.8 is very shallow but again, perfect at the edges. I tend too shoot wide open quite often and with the tracking & eye tracking at 20fps of the Sony A9 cameras you are pretty much guaranteed to get the shot you want. Even with the A7rmk4 etc, they are very sharp up to the edge but again, two cameras with a couple of lenses etc and you are carrying some serious amount of £.  

 

If I wasn't shooting for work... I would still have the A9 & Leica Q-P but I wouldn't bother with the top end lenses. The A9 is great for kid shots!

[charlesphoto]

My Leica M lenses, all bought used in the first place, are the only pieces of gear I own that have actually raised in price over the years. Same can't be said of too many HiFi pieces. The old adage "never sell a Leica lens" is true, as you'll most likely just end up buying it again for more money (been there done that). 

[NoNaim]

17 minutes ago, charlesphoto said:

My Leica M lenses, all bought used in the first place, are the only pieces of gear I own that have actually raised in price over the years. Same can't be said of too many HiFi pieces. The old adage "never sell a Leica lens" is true, as you'll most likely just end up buying it again for more money (been there done that). 

 

Similar thing with my work lenses. If I buy the best once I won't have to sell them and waste money later... they should be with me for many many years. I'd never sell my Leica Q-P. That's probably one of the best 28mm lenses I've ever had. I also like the 24mp sensor size. Great balance of detail and low noise at higher ISO's. I was toying with the idea of getting a Sony A1 but might just pick one up in a couple of years time when they drop in price and use the money saved to get an "M".

[charlesphoto]

@nonaim I bought a used Leica Q a couple of years ago. Great camera but returned it after a week as it just didn't do anything for me over my M10 and 28 summicron. That said, if somebody gave me a Q2 I'd happily take it and use it! I like Leica's for the same reason I like Naim - no nonsense, built like tanks, timeless styling, still repairable, vintage just as good as new, and the sound/look is one that appeals to me. 

 

The M11 is rumored for this fall - we'll see. Might drive down the used M10 prices. I picked up the new Voigtlander 50mm APO last week - imo as good as any Leica lens, esp their 8X more expensive 50 APO; they've since come out with a 35 APO, but if Voigtlander make a 28mm APO it should be a hit. 

[NoNaim]

Yeah, a Q would only be of benefit if you needed AF when you have the M10 and 28 summicron. Well, if the M11 comes out this year then by the time the M11 P comes out I should be ready to buy! I just love the finish of the P cameras, and the lack of red dot.  

[charlesphoto]

14 minutes ago, NoNaim said:

 I just love the finish of the P cameras, and the lack of red dot.  

Yeah, I've never owned a P model M, but do love the look of the silver M10-P with no red dot. I've had my eye on a used model, but just not sure I want to go through the hassle of buying and selling. I got my black M10 the month it came out (upgrading from an M9, also purchased first month of release, coming from an M8) and it's been flawless. 

[accwai]

On 5/29/2021 at 7:06 AM, yamamoto2002 said:

I'm also curious, large aperture prime lenses always disappoint me for poor corner sharpness even on F5.6 ～ F8.

For example, my Nikon AF-S 24mm F1.8 is better than AF-S 24mm F1.4

 

24/1.4 is a strange case. On the Canon side for example, the 24/1.4 has better construction quality than the 24/2.8. So the max aperture got mixed into product tiering consideration. But once one has decided on the bigger one, how would the f/1.4 be used for real? Most of the 24mm f/1.4 images floating around on the net seem rather contrived. Actually it's already bad enough to find good use case for 35mm @ f/1.4, the significantly wider 24mm would be even more difficult. Alternatively, architecture lenses are specifically designed to have uniform resolution across the field and minimal rectilinear distortion. The smaller max aperture could well be a worthwhile tradeoff for some:

 

 

Quote

And wide aperture of lenses cannot be used anyway.  It is waste of sensor resolution

 

Actually fast portrait lens often has a specific look that makes its own kind of sense:

 

 

Probably less than 10% of the area above is actually sharp. In this case, the sensor resolution is used to describe how blazing sharpness melts away. So it's not like resolution is completely wasted. Similar situation with going longer:

 

 

Only part of the head is absolutely sharp, but the image as a whole doesn't seem questionable. Similar for going even longer:

 

 

And believe it or now, the place where one really want to keep aperture big is high macro:

 

 

If one tries get to more depth by stopping down, after certain point everything turns into mush real fast due to diffraction...

[NOMBEDES]

The only wall on this site should be by PINK FLOYD

[accwai]

On 6/1/2021 at 2:28 PM, NOMBEDES said:

The only wall on this site should be by PINK FLOYD

 

Would the illustrious members of AS be so kind as to accept this wall then?