Stupid Question: Crop

[Kris]

Hi Guys

Can anyone help me with the crop tool? The 5D has a few pixels (12.7million) that I believe will allow me to magnify as I call it (or crop) in, usually I think of crop as just trimming each side of an image. My question is: how can I do this, whilst also magnifying ? that is zoom into a part of the image that perhaps is needed if my lens doesnt have enough reach?

Further, how do I go about doing this as to retain a print size such as 6x4, 8x10 or similar so I can print it correctly?

Thanks guys

[bwhinnen]

Depends on how far in you crop. The more you crop into a frame the more it will appear to be zoomed in. Obviously this will exacerbate anything that is not quite right with the image, i.e. softness or slightly out of focus, wrong DOF, noise etc.

The best way I've found to do this depending on the resultant print size is to 'pixel peep' by which I mean look at it at 100% or even 200% on your monitor and see if what you are intending to display is nice and clean.

I know Photo King have recommendations for file sizes related to print size at 250dpi of about 4+Mb for 6x4, 16+Mb for 8x12 and 38.5+Mb for 12x18. These are in uncompressed (i.e. Level 10 and above) JPEG images.

EDIT: Oops I deleted the bit about increasing the size... You need some graphics tool to do this, PS allows a image to be increased in size using the bicubic method that works quite well to increase the image size, as above try and keep a minimum of about 250dpi if possible for printing. I know on my lowly Canon iP4300 we can print a 6x4 or A4 from a uncompressed JPEG version of a 6MP RAW image from the D70 and they come out perfect.

Hope this helps a bit.

Cheers
Brett

[BT*ist]

(apologies for some of the repetition from the above post - I started typing it before bwhinnen posted, AND it's less technical, AND I submitted it later!)

Hello,

Hope I've understood the question correctly, I'll try to answer below.

My camera is a 6.1MP DSLR, and the size on an image it takes measures 3008 pixels x2000 pixels. This gives me a fair bit of latitude to crop in further but still retain a relatively sharp image, because to my view, an 'okay' standard-sized 6x4 inch photo can be made out of an image that is 500 pixels wide (though your view may differ).


Here's an example of a full photo (3008 pixels wide) and what it would look like as a 6x4 inch photo. Heaps sharp for my purposes (I had this enlarged to A4 size).



If, however, I crop the image to one that is 66% of the original (2000 pixels on the longest side) - in effect a digital zoom by cropping- the photo would look like this (I reckon this is okay):



I can also crop to 1/3 of the original's width (1000 pixels) and still get a photo that would look okay:


Finally, a crop that represents only 1/6 of the original photo. This showcases the lack of sharpness in my photographic skillz, and I'd probably not get this developed!:


Bottom line is you'll need to take a look at how sharp the photo is to determine whether it can stand to be cropped heavily. Obviously with a 12MP camera your original image will be even larger. My advice would be that if you view a cropped photo at a magnification equal to that which you're intending to have it printed, you'll be able to make up your mind.

[Kris]

BT*ist, that is exactly what I'm talking about. I see a part within a image, say your billboard that I want to enlarge and print.

So to DO this, you just use the CROP tool in Photoshop? If you set the size of the tool to 8x10 am I right in saying you can crop a section that will mean it will print fine out on a 8x10 print?

Edit: just used my crop tool around some faces in a photo, all it did was basically resize my image and cut out what I didnt want. It didnt enlarge it at all

[BT*ist]

I usally crop using the marquee tool to select the area (style : constrained aspect ratio, width 1.5, height 1) and then click on crop. The I look at it on 'view' at 100% (and/or at the magnification that approximates what I'll be printing it out as).

Alternatively, (and I think I might be the first person in history to suggest this), you can use the quite useful Microsoft Office Picture Manager, which I've found has an intuitive interface. Here, you select 'Picture' then 'crop' and on the menu on the right, select 'aspect ratio' (6x4). As you play around with the size and location of the movable rectangle, the right hand side gives you a 'Picture Dimensions' information that you can use. This might be easier than photoshop.

[Kris]

Ill try this out Thanks!!!

[Heath Bennett]

If you play with the crop tool increments (width/height and res) you can crop whilst actually adding pixels too.

[Kris]

If you play with the crop tool increments (width/height and res) you can crop whilst actually adding pixels too.

Heath, such as changing the resolution to say 400 from its 300 default?

or if you make it higher/wider than it really is it will add pixels?

[bwhinnen]

If you play with the crop tool increments (width/height and res) you can crop whilst actually adding pixels too.

Heath, such as changing the resolution to say 400 from its 300 default?

or if you make it higher/wider than it really is it will add pixels?

You add pixels, keep the resolution the same at 300dpi, but add pixels to the width and height. I am pretty sure it will give you a check box to carry this out using the bicubic method when you do it (sorry on work laptop no PS installed to take a screen shot).

Cheers
Brett