[MJ43]

3 lenses on a K3 MkIII all at 200mm, F5.6 similar light (not great it is a UK summer's day) shot over a few minutes (using TAv), stabilisation off, on a tripod, 2 second delay.
Without looking at which lens is which is there any discernable difference.
Lens No.1

Lens No. 2

Lens No. 3

Without looking at which lens is which. Which lens would you buy?

[HarisF1]

I prefer the output of 2 and 3 compared to 1 but can't tell if it is due to lighting or lens quality.

[Viking42]

Lens 1 seems to be the least sharp, and appears to lack contrast and "bite". Not especially impressive, I'd say.

Lens 2 is much improved on both counts, and has nicer colour rendering and a pleasant contrast.

Lens 3 seems to have similar sharpness to #2, and has significantly more contrast.

Personally, I find I prefer lenses that have less aggressive contrast to be more pleasing in their rendering, which rules out many modern lenses for me. For that reason I would pick #2, but that gets down to personal taste.

Edit: lens 3 certainly is able to pick out some fine details in the bark, etc. Overall rendering is very "lively". The other two look a bit dull by comparison. Both #2 and #3 have their merits.

[pschlute]

You have overexposed the test ruler.

A bit difficult to rate lenses in this situation.

[aldo taddia]

The number 1 is underexposed, and the ruler is more readable.Number three seems to me to have higher resolution and contrast. It's my favorite.

[marcusBMG]

I assume those are 100% ie 1:1 crops.
I would suggest there is little significant difference between these 3 lenses. The more I have tried to take comparison images to discriminate between lenses, the less convinced I have become about the results, apart from very clear differences. All else can be slight focus variation, light variation, external factors eg atmospherics, internal or post processing variation. Indeed the more processing improves (tailored for a particular lens), the more significant that becomes.
That is not to say that a different image set up might not show more differences between the lenses.

[wadge22]

This feels a bit like "corporate needs you to find the differences between this picture and this picture."

I would say 1 is slightly less sharp and lower contrast, 2 and 3 are close enough to the same that they may as well have been the same lens. Colors come out a little different in each, I like 2 best (slightly) for its colors, but I bet it's just lighting related.

Is this three copies of the same lens? If so, go with the cheaper (or the prettier if you're "flush" enough) of #2 or #3.


...
"They're the same picture."

[dbs]

The framing of no 3 would suggest to me its at 180 and not 200 if the tripod has not been moved.
On what is displayed no 2.,

They are all very similar though just the exposure is not equal for the three

[wadge22]

The framing of no 3 would suggest to me its at 180 and not 200 if the tripod has not been moved.

I sort of thought that as well, but I was equally guessing maybe just a tripod bump.
Now I'm confident it's different FL or crop. Note #3 has more bottom right blue flowerpot than #2, as well as more of the tops of the sticks in top right. Also location of the grayish leaf in top left.

So I'm gonna retract my 'three of same lens' guess.

Also, looking closer;

-#3 is most overexposed, and probably least comparable because of it.
-#1 is more 'inferior' than I had originally thought (all three are fine, of course). Less detail in the background all over, although it may be focused slightly closer (note detail on bottom center signpost) which could account for that.
-#1 shows more purple fringe, easiest to spot at bottom of ruler sheet. #2 is best in those regards, and I would say that #2 doesn't have any noticeable purple fringe.
which leads me to
-#2 is actually 'superior,' including to #3 which I initially thought was a tossup. Look at detail on the sub-fuzzies on the fuzzy-thing due right of the 90 mark on the scale. Also look at details on the flowerpot in bottom right. And at details in the grayish leaf top left.

This contest is fun. I sure hope I'm eligible to win all these lenses

[MJ43]

The framing of no 3 would suggest to me its at 180 and not 200 if the tripod has not been moved.
On what is displayed no 2.,

Correct, whilst I set all to the 200 mark on the lens, that one came out at 190 according to the info on the picture. Tripod remained the same for all 3. Slight difference in height if the lens was on the tripod or the camera on the tripod.
On exposure as mentioned TAv so camera set the ISO, I think 2 of the pictures are at 1000 and 1 at 1250.
It wasn't the best day, I was just setting up the focus on a lens and thought it would be interesting to compare.
I have two more lenses that cover 200mm so will repeat the experiment with the 5 lenses but on a bright day - no clouds - and with a better defined subject to see how or if the lenses 'pop'. I will also take more care to make sure the framing and length in each case is the same. I will let the camera decide the exposure.

I must say the result/comparison was not what I was expecting - but that might be the subject matter, hence a second test when the conditions are right (a sunny day in the UK - I wish)