Zooming on Computer, vs. Cropping with Pixelated Results... Confused.

[PlacesAtNiagara]

Hello all, I've been a member for about 30 minutes now, and this is my first post. I'm very much a beginner. Glad to be with you all!

I took several photos of a Memorial Day Parade in my little home town, and I noticed something later which puzzles me. Once my photos were on my computer screen, I could zoom into them so deeply that I can see details as small as wiskers perfectly on the faces of some of the guys in the scene. For fun, I thought I'd play around with cropping and resizing to see if I could make usable photos from the image on my screen which was 'zoomed in' very close. (You probably all know what's coming next) When I cropped and resized, the results were pixelated and terrible.

A call to my camera store told me that I was sacrificing pixels when I tried to crop and resize, and I 'almost get' what they are telling me... but I'm still confused. If zooming in on the computer screen can reveal such amazing detail, why is that detail lost when I try to crop a small section of the image and then resize it to a standard size? Is there any way to tap into that amazing detail? If not, why would such detail only reside on a computer screen and not be available to a cropped photo? Is there a way to make photos work in this way that I don't know about? (Just curious.)

Hope my first post makes sense. Thanks! -- Greg

 

[Bitter Jeweler]

It's the resizing that kills it. The software has to "create" pixels to fill in the information.

 

[Kerbouchard]

If you are taking a small part of the image and expanding it to standard size than you are telling the computer to create pixels from nothing. Now, if you take a small part of an image, and display, or print, it at it's standard size, the detail will be there.

For instance, let's say your picture is 3000 pixels by 4000 pixels. If you view it full size, than on your monitor, which may only be 1000 or so pixels across, you will see the image as 4 times larger, therefore you will see the detail. That is fine. Now, if you take that 1000 pixels and try to make it standard size, i.e. 4000 pixels, the computer has to guess what pixels would have been there.

There are programs that do it quite well, but they aren't cheap. So, basically, your dissatisfaction is probably a mixture of your crop and resize method and your expectations.

 

[Josh66]

If you crop, and then resize (to a bigger size), it's not going to look good.

If you just crop, and don't resize, it will look better - but you won't be able to print as large (or you will run into the first problem again).

Depending on how large the original is, and how much you're cropping - you may still be able to get satisfactory results.

 

[PlacesAtNiagara]

Ok I understand that...Thanks! As for that software which can resize with good results, about how much does something like that run... just a ballpark guesstimate? Sounds like the easiest way to get better results would be to take better originals to begin with.

One thing I learned from my Memorial Day, people-shooting photo session is just to keep on clicking and move in a little closer. Folks at the parade thought I was with a local newspaper and nobody minded that I was shooting their photos... so it would have been easy to move in even closer and fill up my viewfinder with their faces... sure regret not doing that now, but live and learn!

I have lots of county fairs coming up to photograph, as well as Ohio State Fair, July 4th, etc. to make improvements in my shots... looking forward to it!

Thanks for the clarification Folks! -- Greg

 

[Dao]

A telephoto lens with longer focal length will comes in handy so you do not need to walk too close to the subject.

 

[Aze]

Ok I understand that...Thanks! As for that software which can resize with good results, about how much does something like that run... just a ballpark guesstimate?

Unfortunately the answer to your question is, no amount of money. Forget about everything you've ever seen on TV of someone taking a tiny, fuzzy picture and blowing it up into a clear detailed picture, it just doesn't happen. I could go into a long explanation about how image processing works, but the simplest explanation is, you can't show something that isn't there.

 

[ann]

You could take a look at a program from OnOne called Genuine Fractals, it will upsize. Runs under $200 if i remember correctly. However, as Aze mentions nothing will work if you have cropped away too much information.

 

[PlacesAtNiagara]

Ok... sounds good. Going to put it out of my mind and just concentrate on getting the shot right in the first place.. Thanks! As for the telephoto lens, I have an 18-200mm which ought to be fine for now.... hopefully!

 

[o hey tyler]

Ok... sounds good. Going to put it out of my mind and just concentrate on getting the shot right in the first place.. Thanks! As for the telephoto lens, I have an 18-200mm which ought to be fine for now.... hopefully!

The 18-200 is not a great lens for optical performance. It's main use is based on convenience.

 

[PlacesAtNiagara]

Ok... sounds good. Going to put it out of my mind and just concentrate on getting the shot right in the first place.. Thanks! As for the telephoto lens, I have an 18-200mm which ought to be fine for now.... hopefully!

The 18-200 is not a great lens for optical performance. It's main use is based on convenience.

You are correct, I suppose, at least according to what your own definition of what 'great' is. For myself, it truly is a great lens.. just awesome. My uses however are only to put great photos on a website, and I doubt any of my viewers will ever be passing a 10X loupe over the screen to see how sharp the details are. Were I a photographer for National Geographic, I'd need to spend a lot more money... so it's all what you want to use it for. Still... I can't believe how nice the photos are... if we are talking flaws, only experts who know what they are looking for could find them... certainly not any of my future web viewers. No complaints here. (I'm not the only one who feels this way... just go to Ken Rockwell's page and read his comments about this lens.)

One thing I do know -- even as a newbie -- is that two sentences of commentary doesn't begin to tell the story behind this lens. The optical performance may be a bit under a lens with a fixed focal length, but I simply recognize that to be an engineering trade-off. What I get in return is a lens which lets me do nearly everything I want to do in a crowd of people. You are very correct about that lens being convenient.. but to someone like me, that statement is way understated... kind of like saying a Ferarri's main use is based on speed. To me it's just fantastic. I put it on when I purchased it with my camera and have yet to take it off... I think that's the part I love the most. It handles 90% of what I need it to do and that's just fine with me. The other 10% will come later... I am patient. I really want a dedicated macro lens... probably with another camera body as well, since I am sold on the convenience of not having to change lenses.

 

[o hey tyler]

Ok... sounds good. Going to put it out of my mind and just concentrate on getting the shot right in the first place.. Thanks! As for the telephoto lens, I have an 18-200mm which ought to be fine for now.... hopefully!

The 18-200 is not a great lens for optical performance. It's main use is based on convenience.

You are correct, I suppose, at least according to what your own definition of what 'great' is. For myself, it truly is a great lens.. just awesome. My uses however are only to put great photos on a website, and I doubt any of my viewers will ever be passing a 10X loupe over the screen to see how sharp the details are. Were I a photographer for National Geographic, I'd need to spend a lot more money... so it's all what you want to use it for. Still... I can't believe how nice the photos are... if we are talking flaws, only experts who know what they are looking for could find them... certainly not any of my future web viewers. No complaints here. (I'm not the only one who feels this way... just go to Ken Rockwell's page and read his comments about this lens.)

One thing I do know -- even as a newbie -- is that two sentences of commentary doesn't begin to tell the story behind this lens. The optical performance may be a bit under a lens with a fixed focal length, but I simply recognize that to be an engineering trade-off. What I get in return is a lens which lets me do nearly everything I want to do in a crowd of people. You are very correct about that lens being convenient.. but to someone like me, that statement is way understated... kind of like saying a Ferarri's main use is based on speed. To me it's just fantastic. I put it on when I purchased it with my camera and have yet to take it off... I think that's the part I love the most. It handles 90% of what I need it to do and that's just fine with me. The other 10% will come later... I am patient. I really want a dedicated macro lens... probably with another camera body as well, since I am sold on the convenience of not having to change lenses.

You didn't read my post. There is no measure or test that will say the 18-200 is (optically) a great lens. If I remember it correctly, Ken Rockwell enjoys the lens mostly for the convenience and close focusing ability. .

So yes, while it may be a great lens for your purposes. That doesn't change the optical attributes of the lens. Jack of all trades, master of none, etc.

 

[PlacesAtNiagara]

Ok, well maybe your post didn't show up too well on my screen. I only saw two sentences. Anyway, I stand by what I said (although I see your point.) My point is that it gets the job I need done in superlative fashion... worth every penny of its $850 price tag. Forgive me, but based on what I saw of your comments (two sentences) it sort of left me cold... I know the lens is far better than the impression which could be cast from such a brief comment. Thanks!

 

[KmH]

When you crop, you throw away pixels.

What was a 3000 pixel by 2000 pixel photo, is say, a 1000 pixel by 500 pixel photo after cropping. If you then resize larger what is left after the crop, you are also making all the remaining pixels larger making them easier to see individually.

 

[PlacesAtNiagara]

Yes this now makes perfect sense to me... thanks for replying. I'm kind of embarrassed that I didn't figure it out on my own.

I'm actually glad that it's not a simple matter of cropping a section of a photo you find interesting and then resizing it to make a usable photo... I realize now that when I'm using my camera, careful composition of my shot really does matter... and this can only force me to be a better photographer. (Thoughts of a newbie... probably nothing new to you veteran photographers out there!) I've since taken 'practice shots' of my family around the yard just to get a feel for how close I have to get for the results I seek, and I'm still very pleased. The next time I'm out capturing candid shots of people, I'm confident they will be much better photos.) Thanks again to all who helped clear this up for me! -- Greg