I must be losing the thread here ............. which "Particular exact effects" are you talking about that "no one has yet shown it can be done"? Has the RAW file been made available for others to try?

Andrew

I use PSE8 which incorporates ACR6.2 and it is plenty good enough (for me). I also have installed the latest version of RawTherapee. It is fundamentally a RAW converter rather than an image editor. It is at least as good (I really mean much better, but then someone would probably argue if I said that) than ACR6.2 and has massively more functionality. It also has a huge learning curve, which is why I only use it when I absolutely must have the best quality RAW conversion possible.

Might be worth a look ..........

Andrew

Yes, I agree with that, providing that you insert the words "most obvious" before "difference". It is true also that there are noticeable differences in detail between the two images, which could result either from the inherent capability of the software - or alternatively from the skill of its user.

I must admit, that I am generally in the camp that believes that there are several photo editing software programs than can, if used skillfully, produce (almost?) visually indistinguishable results - especially when viewed as such a small image on a computer monitor.

Andrew

It might be worth considering using one of the freebies too - such as RawTherapee. It is reputed to be at least as good a RAW file developer/converter as any commercial software.

Andrew

No, I don't think so. Both photos are the same size in memory. The difference in file size results from the operation of the JPEG compression algorithm in Photoshop Elements 8, which I used to save the photos onto disk. Compression algorithms work on the basis of eliminating redundancy in a file. The greater the number of different byte values in the file, the less it will be possible to compress it. As Image 2 is smaller on disk than Image 1, it must have had greater redundancy (repeated similar values) in the original image and hence less detail.

Andrew

I agree with most/all of the above comments about No2 being way too blue. There also seems to be less detail than in No 1.

If you copy both of these into Photoshop (or PSE8 in my case) and then simply save them as JEPGs without any processing at best quality, the file size for No 1 is 161kB and for No 2 is 153kB. The greater JPEG compression for No 2 suggests that there is greater duplication in the image and hence less detail.

Andrew

Possibly slightly - but mine is pretty damned good everywhere!

Andrew

Indeed yes, but if you repeat a comparison between two lenses with different subjects at different distances several times - and the result is always is in favour of Lens A rather than Lens B, I think you are entitled to conclude that for the actual samples you have, Lens A is sharper than Lens B. You are not, though, on the basis of any series of comparisons between a single pair of lenses, entitled to conclude that other samples of the same lenses would produce the same results.

I am sure that you are right that focus accuracy is by far the most important source of potential error in lens testing and comparisons. Whilst testing used lenses that I have bought, I usually take several shots of the same target with a lens, in the same lighting, at the same aperture, shutter speed and ISO setting - all of them seemingly perfectly focussed using a split-image focussing screen and dispaying the focus confirmation symbol, yet on pixel peeping, they are not all equally sharp.

Testing is, though, useful for quickly identifying the turkeys that you (I) have bought in your (my) continuing search for the Holy Grail - i.e. a cheap old lens that is as good or better than the modern one that you (I) should probably have bought in the first place.

Andrew

Agreed - and differences between lenses often seem to shrink or evaporate completely in real world photography (i.e. when not pixel-peeping). I do worry, from time to time, that I just might fluke a decent shot - in which case, I'd probably feel better if I had my sharpest lens on the camera at the time.

Andrew

I use a K200D, so I don't have the option of micro-adjusting focus for each lens. The best lenses in use are those that produce the best results irrespective of any micro-focussing errors that could theoretically be corrected if I had a different camera. In real use, I usually verify focus both using the split-image focussing screen and the K200D's focus confirmation - just as I did with the test shots above. Practically, there's no obviously better way of doing it.

I'll be doing some more testing if it ever stops raining, but at the moment (at 50mm focal length and an object distance of 3m) the F 35-70mm seems to be producing sharper images than the kit lens at the same aperture - and similar (or better) even when one stop wider. I acknowledge that testing at different focal lengths and different object distances might produce different results.


Andrew