crop quiz

[arash_hazeghi]

Just for fun and after a recent thread (by Bill Dix) about cropping I wanted to see if you anyone can guess the crop percentage for this image

this is by no means a great image, but it serves the purpose for this experiment.

[Jonathan Ashton]

The displayed image is 1920 px wide, I would imagine that the preceding TIFF would not have been a great deal larger than this.... unless it has been interpolated or gigapixeled at some stage. The image is well exposed, focused and processed so the inherent display quality is good but looking at the image I would guess the pixel count was quite modest. Purely a guess but I would not be surprised if this was cropped to somewhere around the 2000 -2400 pixel prior to presenting as the 1920px image..

[Andreas Liedmann]

Hi Arash .... would like to vote .
But never understood how to really measure the correct percentage of my crop . Was more or less guessing ... i would be more than happy if you could light up my brain !!!

Thanks andreas

[John LeClair]

Good question Andreas. I always assumed it was a percentage of total pixels. I.E. if the original was 1000 x 1000 pixels you have a total of 1,000,000 pixels. If you cropped it to 750 x 750 you now have 562,500 pixels. That translates to 56.25% of the original pixel count. So you cropped (removed) 43.75% of the pixels. A 43.75% crop.

That's what I have assumed.​

Also, I think Johnathan's guess is pretty reasonable. If I had to guess if he was over or under, I would say he's over.

[John Mack]

I guessed 80%. Will be interesting to see what the real crop is.

[dankearl]

I am going to say just a 50% crop because why would you press the shutter if it
was any farther away than that?
Especially against sky where you could get focus anytime you want and shoot very low iso...
Maybe wrong though, and you took one a mile away just for this exercise.

[arash_hazeghi]

I was hoping for more responses before I reveal the answer :)

[Alex Becker]

I like these types of games and think they are informative -- I'll guess 20% of the original. It's hard to know without knowing the camera body and techs used (but just for fun, I'll guess 1/3200 f/5.6 and ISO 640 ?), but the image is clearly sharp. Arash, could you post the straight out of camera frame whenever you post the answer? I'm just curious what it looked like on capture given whatever number it ends up being. TFS

[Andreas Liedmann]

As the detail is not well defined .... and lacking critical sharpness ... i think 20 % of FF .
But then i am asking how small is the subject in the original ....? :w3 In the end it is just a funny guessing

[arash_hazeghi]

As the detail is not well defined .... and lacking critical sharpness ... i think 20 % of FF .
But then i am asking how small is the subject in the original ....? :w3 In the end it is just a funny guessing


I will reveal the answer soon
I think because you have probably never seen a peregrine falcon you may not know what to expect i.e. what a sharp peregrine photo actually looks like because this one is definitely sharp so I will post another image for comparison

[Andreas Liedmann]

Hi Arash ... no problem if you say so .
See it differently ... has got nothing to do with the subject if an image is sharp or not .... IMHO .

BTW i have seen a peregrine falcon before ... closer than you might think .

[arash_hazeghi]

Hi Arash ... no problem if you say so .
See it differently ... has got nothing to do with the subject if an image is sharp or not .... IMHO .

BTW i have seen a peregrine falcon before ... closer than you might think .

I have to disagree not all birds look the same and sometimes the plumage can play mind tricks if you haven’t seen one before. As noted by others this image is sharp so we must have different perceptions. Do you have any photos of the peregrine falcon to post here for comparison ?

[Andreas Liedmann]

Arash .... i do not have an image for comparison , sorry .
We all have different perceptions at times , and we all look at different screens so even if others say this or other images do look sharp .... i might agree or disagree . And for me it is totally ok ... to have different views of the same subject , just have to accept other opinions .

AS stated above for me it does make no difference which subject is shown in an image , whether it is a bird shot , landscape , wildlife , human being etc .... it is all about the original structure of the subject . Surface might be smooth or detailed and very defined ..... some folks folks have smooth skin other folks have rough skin . Just my 2 cents .

[arash_hazeghi]

some folks folks have smooth skin other folks have rough skin . Just my 2 cents .


correct so without knowing if the skin was smooth or rough you can't make a comment about sharpness where there is no texture :)

[Andreas Liedmann]

I can ... by looking at the edges like i.e. eyelashes and other things in the human face :w3

The same with feather edges or animal fur , as in your example one can see where the sharpening took place

[arash_hazeghi]

I can ... by looking at the edges like i.e. eyelashes and other things in the human face :w3

The same with feather edges or animal fur , as in your example one can see where the sharpening took place


You think you can... :w3 any ways wait for the answer :)

[Andreas Liedmann]

We all can ... see sharpness , just with different perception . One does not need to be a guru ....:w3
Think we come not to an agreement , and honestly it is not so important for me , if this image is sharp or not .
Thanx for the exchange ... Arash
Make this forum alive .... :bg3:

Regards Andreas