135mm F3.4 Apo Flaring?

[pgk]

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FWIW this thread got me thinking and so I tried my 135mm lens (the previous non-apo version - I have the E46 version) hard into the sun which was kept slightly outside the frame. I am surprised at the results and the lack of flare. All I can think is that the E46 lens design  is well thought out in terms of minimising internal flaring. It is also spot on in terms of focus - unlike the 3 x E39 versions I have owned previously. I wonder if the E46 version was built to address issues and whoever designed the mechanical side had a very good idea of how to deal with flare and ensure focus would be as precise as possible. Someone was good if so because they succeeded.

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[wattsy]

I don't know about your E46 lens but you were lucky to have some sun today to shoot into. Relentless rain from dawn to dusk here.   

[Ozytripper]

Sorry, just a silly question. I noticed that the photo I posted of the M10 with 135mm n hood is "bubbling" and the image is falling apart. Is it because of the small size file?

I don't do social media so I have never looked at my photos in such a small file. Same thing happened to the flamingo shot I posted in another thread.

[adan]

Yep - jpeg compression artifacts. You are compressing about a 3 Megabyte picture file to 127 Kilobytes (1/20th or 5% the amount of data). Something has to give.

 

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

 

To shrink the file that much (data size compression, not physical or pixel dimensions), a lot of pixels have to get sort of averaged together (non-technical explanation) and that shows up as "bald spots" in the fine detail and a general "moth-eaten" look (e.g. around the engraved type on the lens barrel). Slightly more technical, the averaging is applied to 8x8 pixel areas, "collapsing" all 64 pixels to one tone/color, approximately - those 8x8 squares are actually becoming visible in your highly-compressed file. See blowup of a crop of your posted image below.

 

It is "lossy" compression - the detail that was once there is gone forever, in the jpeg you posted (your original picture is, of course, fine.)

 

The limit per picture on the forum is 500 Kbytes per post, so you could have compressed it a lot less, and seen far less damage, and still posted a picture that "large" in terms of size on screen. As you save your image as a jpeg for posting, usually the compression software (LR, PS, whatever) will tell/show you how big the final compressed file will be, and you can adjust the quality setting (higher quality = less compression) until the file will just squeeze under the 500K limit.

 

Put another way - your uploaded file was squeezed to 127 Kb. I brought you picture into Photoshop, added some noise to restore "detail" or texture to your picture (to simulate the "bubbled" detail that you lost that was in the original) and my PhotoShop compression algorithm required a quality setting of:

 

19 (out of 100) quality - VERY LOW - to squeeze it down to 127Kb again (what you did)

86 (out of 100) quality - VERY HIGH, to get the same picture to be just under the 500Kb limit (496 Kb - what you COULD have done).

 

Usually, when you save as a jpeg, any quality setting above 75-80 or so will have relatively few artifacts visible (perfectionists will disagree!), so you don't HAVE to use a higher quality setting. Obviously an "informational" picture like your lens shot is not as critical for quality as a sample (e.g. flamingo) where you are trying to SHOW the quality of a camera or lens or your focusing skills, as such.

 

Blow up of your compression artifacts - the algorithm tries to maintain sharp edges in some places (around lettering or other fine detail, for example) - but has to make up for that by crushing the fine textures in 8x8-pixel blocks everywhere else.

 

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[adan]

One other effect may be happening as well, in the couch cloth texture - Moiré patterning.

 

ANY digital picture is a checkerboard pattern of square pixels. If a picture contains a real-world repeating pattern/texture that is very close to the pixel checkerboard in spacing, the two patterns can "interfere" with one another to produce a moiré pattern - a third "phantom" texture: http://cdn-10.nikon-cdn.com/kdb/moire/moire_forms.gif

 

You can get a moiré at the time of taking the picture (real-world texture and camera's pixels). OR, you can get a moiré later on, if you happen to reduce a picture in resolution such that the real-world texture shrinks to the size of the final image pixel spacing.

 

For quite a while, all digital cameras had an "anti-aliasing" or anti-moiré filter on the front of the sensor, to blur the picture slightly to avoid in-camera moirés, at the cost of a reduction in resolution. Medium-format pro cameras - and Leica, starting with the M8 - began leaving out such a filter, accepting the occasional moiré artifact in return for sharper pictures. Many other camera makers (Fuji, Nikon D800E, etc.) have joined the club, as it became apparent that many photographers would accept that trade-off, for sharper pictures.

 

[Ozytripper]

Thanks Andy. Nice detailed explanation.

 

Being an old goat who is shy of social media have just learnt something new.

 

I used to shoot Kodachrome exclusively so I tend to just use SOOC JPG images albeit with just some cropping and the occasional exposure adjustments. I do shoot in JPG and Raw and just keep the RAW files just in case I want to process them one day. Maybe I should find time to use computer software more. I do have a copy of photoshop but most of my cropping is just done on whatever comes with the Windows 10 software  

 

The Flamingos shots were just a quick test of the 80-200mm setup with my new R Apo macro adapter. Workable but at this stage I will stick to my Fuji Xt2/Xpro2 and my fuji 100-400mm. 

 

I am at the moment having lot's of fun with the 135mm F3.4 Apo. Now the flare is gone (almost) it gives superb photos. Maybe the thinner Pentax 135 150 200 hood will further eliminate the little flare that is left.

 

Yes I am quite familiar with the Moire effect - get that in the Fujis too as they don't have AA filters.

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Sorry, just a silly question. I noticed that the photo I posted of the M10 with 135mm n hood is "bubbling" and the image is falling apart. Is it because of the small size file?

I don't do social media so I have never looked at my photos in such a small file. Same thing happened to the flamingo shot I posted in another thread.

This may also be helpful:

 

Why does the forum shrink my photos and adds ugly artifacts?