Why not include crop amount with techs

Just wondering why a majority of people do not include the size of the crop (in percent of FF or equiv, not small, med, or large as this does not provide much usable info to the viewer) for each image they post along with the other techs (ISO, f, SS) that most everyone includes? Purpose of this thread is to open a discussion on this subject. Cheers.

Good question and worth asking.

I try to include a % of frame with all my posts, but I sometimes resort to simply saying something like "modest" or "moderate" crop. If I'm posting just after prepping the image then I make sure to calculate the crop percentage by noting the dimensions just after I crop in Photoshop. If I'm not expecting to post immediately I will enter the cop percentage in the metadata so I can retrieve it later.

But I often end up parking the cropped 720 and 1200 pixel versions in a folder for future posting and don't have a convenient way to recall the crop percentage when I get around to posting the images. I could recalculate by digging out the saved file, but they are stored on an external firewire drive off my other computer at the other end of the house and it is just too much bother to go there, start up the desktop, turn on the FW drive, find the proper file, and then figure out the %. I really need to remeber to put the value into the metadata every time!

Rich, I have the same issue sometimes. I have now resorted to doing just what you mention, adding the crop percent in the metadata for each image, that way I always have it. Besides not having the info handy, I wonder if there are other reasons why many do not include it. Is this info deemed not valuable by most, so they do not include it. I believe it is very valuable to people trying to provide a good critique of an image and for people trying to assess the performance of various camera body and lens combos under different shooting situations.

Ron - I don't post it simply because I don't ever bother to calculate it - I don't really have a need to. If I cropped enough just to straighten, or remove some distracting element, I'd say "slight crop" when posting. Any large crop and usually I'll take a guess, but in rough terms, like "about 1/2 of full frame", etc.

I'm not sure what the benefit is to knowing that someone has cropped an image, other than whether or not it would hold up at larger sizes. In that case, rough terms are plenty accurate enough I think. Is there some particular reason you want people to bother to calculate it?

Yes, calculated it and provide it, for the same reason it is nice to know the lens, f, SS, ISO settings. It is data that helps me provide a good critique of the image posted in a critique gallery. It also helps me learn and understand how different cameras perform under different, real-life conditions. Example, if I see less detail in an image than I would expect, it could be ISO (introducing noise), or it could be a large crop, or it could be a panning issue. With both pieces of data I can make a more imformed critique, without both or one or the other what can I really say. That is just one simple example. Using vague terms like small and moderate really do not help, as one person may see an image that is 45% of FF as a moderate crop and others may see that as a large crop. Giving the percentage of FF leaves nothing to be guessed at.

In response to David's comment:

1. Looking at your gallery I don't see any avian images, and I think that puts you in a different class of photographers from Ron and I. Note that Ron made his post in the Birding Forum: I thought at first that this would have been better in the general forum but I suspect this is an issue primarily for bird photographers. Perhaps Ron will expand on why he placed it here.

2. One of the major challenges of bird photography is getting a reasonably sized subject in the frame. For the most part birds are rather small, and unless you work at a backyard feeder setup getting close to small wild birds ca n be quite difficult. Avian photographers normally go with the longest focal length they can manage (both in cost and in physical size), and even then we are often still too far from our subject.

3. So, that leads to many bird photographers resorting to cropping a lot more than non bird shooters. If your subject matter is mostly scenic, then you have the time to choose the right lens and move around to get the coverage you want. If you work primarily with flowers then you can circle around and get closer without your subject flying away.

4. The reason knowing the amount of cropping that was done serves at least these purposes: it lets the viewer know if the photographer was successful in getting close to the subject; it can explain observable issues with image quality; and it educates novice photographers about reasonable expectations about what it takes to take any sort of bird image and what it takes to maintain acceptable image quality.

5. I don't think many people are very good at estimating the amount of a crop. If you do the actual calculation after taking a guess I suspect you will find that you have grossly underestimated how much you have cropped.

See this Cropping example on my web site under the "Calculating Crop Percentages" tab.

I suppose if it was in the EXIF info in Bridge the same way all the other data is, I'd provide it. And I think you're right, Richard, that it's of much more use in images, like a lot of avian, where there's a very specific object that you want to fill the frame (at least to some extent).

(Also, I didn't realize this was posted in the Bird forum....sorry for that.)

I usually provide the crop info, since Lightroom (if I crop there) provides the crop dimensions, making it an easy calculation at post time.

I would provide crop info if it was easily available to me. Philip, could you elaborate on how you do it in LR? Whenever I really need to know the precentage, I calculate it using pixel counts, which isn't that simple.

E.g.

2985 x 2243 / 3648 x 2736 =
6695355 / 9980928 = 67%

There is also the question of semantics in how you word it and people (like me) can be confused if it isn't explicitly stated - say - cropping TO 66% is very different than a crop OF 66%. If it's just a number in metadata it could be more confusing than not.

This is a great post! As a relative newbie, I'll just claim ignorance. First, I never considered how helpful it would be for those critiquing my images. Second, when I saw someone post '82% of FF' I had no idea how they got that figure. Richard, the explanation on your website is very helpful. I will try to include this in my future posts.

Thanks Ron for starting this discussion. I continue to learn a lot from you guys.

I always say "__% of the original frame" that way it is not as confusing as __% crop.

I have forgotten a few times to mention the crop size but I try to post it every time. I believe it is important in avian especially because we can not always get close to our subjects when photographing them in the wild. Secondly, crop size is important when evaluating detail issues, over compression causes loss of detail as well as large crops so I'd like to know which one might be the issue when I am critiquing someone else's image.

I also do not want to mislead new photographers by making it seem that I was right up on the bird when in fact I might not have been.

Calculating percent of Full-Frame is not very difficult. Length of image in pixels multiplied by Height of image in pixels = total pixels of your image. You should know how may pixels a full-sized image from your camera is. You take your final image size and divide it by the number of pixels for a full-sized image from your camera. That gives you percent of Full-frame. Look at "image size" in you image editing software after you crop your image down to the demensions you want it to be for your final image as you are processing your image. Example: Let's say my image is 2133 x 1514 pixels and my camera takes a full-sized image of 18.1 mega pixels (18,100,000 pixels) 2133 x 1514 = 3,229,362 pixels. Divide that by 18,100,000 and you get 0.1784 x 100 to get it into percent and you get 17.8% of full-frame. If you write down your image dimensions when you process each image you can easily calculate percent of full-frame.

There's an easy shortcut to calculating % in Adobe Camera Raw. When you use the crop tool to make a selection, on the bottom of the window, below the picture, it says how many MP your resulting image is. As you adjust the cropped frame, it constantly updates the MP of the cropped image. (And after you crop, this info is still there.) This saves you multiplying the dimensions. Instead, if it says 10.8MP, I just divide 10.8 by 18 (the MP of my 7D) and get the %.

I agree that crop %s are probably most relevant here in the bird photography group, given the difficulty of approaching our subjects and the ability to (unintentionally) mislead by cropping in. I make a point of posting crop %s, as I've found them valuable in learning to critically evaluate others' images as well as my own.

I don't do too much bird photography these days.. but thought I'd offer another point of view --

Why give the crop % when what you're really interested in is what kind of detail is in the image? A 50% crop off a 5DmkII is very different from a 50% crop on a 20D. Why not just list the # of megapixels in the cropped image, which requires no calculation if you crop in the raw converter as Brian pointed out.

Whenever I do post a bird image I've always said something like '5DmkII cropped to 12MP'.

What's the point of talking about something that is no longer there?

Good point Floris. Providing the number of MP in the final image would be a good standard.

Jeffrey, because what is taken away from the origianl image (i.e., pixels) can affect the quality of an image, depending on how many you remove.

if u really want to be critiqued in a proper way i think it's necessary to provide the crop info, i follow the pattern of stating the crop info when i've done an crop, if i've not mentioned it i.e. it's full frame

Ron:
It's has not been my experience that providing crop info favorably influences the quality of feedback about an image. Instead, if the post is a relatively large or even moderate crop, the default comment reverts to "nice detail for such a large crop" and other aspects of the image tend to be ignored.
Dave