Nikon D70 & Photo Resolution

[MichaelRS]

I just noticed that all of the photo's I take with my D70 always import into Elements at a resolution of 300. Does anyone who has a D70 know why? It doesn't matter what quality setting I use, Basic, Normal or Fine, it always imports at 300. I would have thought that the resolution would change with the quality of the setting but the only thing that ever changes is when I change the size of the photo, Large or Small which changes the overall size of the photo but again doesn't change the resolution.

Is this the way it is with everyone's camera? Or is there something wrong with mine? I noticed this because I discovered that anytime I crop a photo I always lose resolution. I thought that if I shot at a higher quality then naturally the overall resolution would increase so that the loss of resolution that occurs when I crop won't matter so much. But, not the case. I'm a bit perplexed by all of this. Any thoughts from anyone?

Michael

[Chuck S.]

Michael, there's nothing wrong with your camera! The resolution number for images being imported is really meaningless; the only thing that counts is the pixel dimensions. In the case of the D70, I believe your images should be importing at 3008 pixels by 2000 pixels.

For whatever reason, each camera sends some sort of flag with its images that sets the resolution and then the linear dimensions are calculated. In your case, it picks 300 - and I'll bet the image size in inches is about 10 inches by 7.5 inches.... But if the camera told PE to use a resolution of 100, you'd still get a 3008 by 2000 pixel image imported, and the linear dimensions would be 30 inches by 22.5 inches! Remember that the linear dimensions don't matter much at all until it's time to print.

Chuck

[Chuck S.]

Re your point about cropping, that gets a little more complicated. Generally, you should crop with the resolution box on the crop tool blank - that way, the cropping won't cause 'resampling' which either adds or deletes pixels to achieve a certain resolution.

When you're cropping without a set resolution, the ultimate resolution 'floats' (i.e., it's recalculated) depending on how much of the image your crop. The act of cropping throws away some of the pixels, changing the image dimensions in pixels. The resultant resolution is derived by dividing the new pixel dimension by the linear (inch) dimension you specified in the crop tool.

I think the best way to get used to that concept is to try some cropping and keep going back to Image>Size>Resize to see what's happened to the pixel dimensions, linear dimensions, and resolution. It takes a while to sink in that it's all about recalculating the relationship between pixel dimensions and linear dimensions...

:)

Chuck

[GaryK]

Michael

I think a lot of the resolution/size confusion comes from the fact, that unless the resolution is VERY low you really don't see much, if any difference on the screen. Add to that the fact that you can drag the size out or in, do adjustments, add filters etc., etc. and still not notice a quality change makes it harder still.

Chucks suggestion about checking the size/resolution frequently, while messing around, is a good idea. You also may want to leave rulers on while making resolution changes and see if that helps.

Try to leave resample unchecked no matter what (at least if you are playing with an original) when you are changing resolutions.

[MichaelRS]

But I thought that you should have a minimum resolution of around 300 for quality photo printing?

Michael

[Grant]

QUOTE=Michael R-S]

But I thought that you should have a minimum resolution of around 300 for quality photo printing?

[/FONT][/QUOTE]

Minimum resolution is a very subjective thing and in this case it's truly in the eyes of the beholder. The photographic bench mark for resolutions is based on observing a photograph at about 12 inches away here is where the average eye can resolve 100 lines per inch. In digital photography you line would consist of the two dots therefore 200 dpi will be the limit of resolution under these conditions. Often a higher number is used to assure that you will get excellent results . Often 300 dpi is a choice many people feel comfortable with. Many printer manufactures use 240 dpi (never mined the hype they use - like 2400 dpi). Then camera companies select values from a high of 300 dpi a lower value of 180 dpi, my Canon G1 was set at this and delivered excellent images. Keeping in mind that some eyes are younger and others are older it is best to stick with the average value to reach the largest audience. For my part I tend to print at 240 dpi but will not hesitate to print at 180 dpi if the subject is right.

[MichaelRS]

I am really having a hard time getting my head around what you all are telling me. I have had people explain this all to me before and for some reason I just don't get this. I'm not usually this dense with other concepts.

I have recently run into a situation that unfortunately is repeating itself. I have taken headshots for actors at our local theater. The problem is that after I crop the pictures the resolution drops to 120.

Is this really a problem? The photos are going to a photo store for processing so I am concerned they are going to come out at less than a professional level. Am I stuck in a situation where I need to resample the photo up to get it to an acceptable level for printing?

Or should I resize the entire photo without resampling it before I crop it? Will that make a difference?

Michael

[GaryK]

Hi Michael

Hopefully one of us will say something that clicks:D

Don't feel bad, it is a strange concept.

You may have to resample those head shots. I'm not sure if it would matter before or after.

The thing is, if you have a photo at 300 ppi and say that photo is 8x10. When you pick the crop tool and use a setting of 4x5, you would be able to drag out the crop box to the full 8x10 size. You would then have a crop at 8x10 at 300 ppi.The image would be resized to 4x5 at 600 ppi (by elelments).
You could also drag out the crop box (on the original image) to a size of 2x2.5, at a resolution of 300 ppi. The program would then resize it to make it 4x5 and the resolution would drop to 150 ppi.

[jimkovacs]

I also have a Nikon D-70.

I rarely use the crop tool for cropping, for the reasons you have cited. You can lose pixels this way.

My primary method for cropping is to use the transform tool, there is no loss of pixels this way. It may take a little more effort but its worth the time.

Remember to hold down the shift key, to keep your transformation in scale.

Try it; use a duplicate of an image, check the size, crop with the transform tool and you will find no loss of pixels.

Also, I'm in the habit of composing within the viewfinder, so usually I have a minimum of cropping.

[MichaelRS]

Jim-
Can you explain how you do that? I'm not sure I understand.
Michael

[Chuck S.]

Jim, just to add to the confusion further: cropping with the marquee tool in fixed aspect ratio mode does exactly the same thing to the image as cropping using the crop tool with no resolution chosen - in both cases, the final pixel dimensions of what's left will be exactly the same. The linear dimensions and resultant ppi may appear different, but the only thing that counts is the size in pixels.

The only time the crop tool adds or removes pixels in the portion of the image that remains is when you specify a resolution; in that case, the tool has to satisfy three constraints simultaneously (length, width, and resolution) so it must almost invariably add extrapolated pixels or delete original image pixels.

[MichaelRS]

The problem I have found with using the Marquee to crop with is that you have to make sure that the actual size outlined is the size you want the crop to be. If you don't do that, say the actual size that you outline is actually 2 inches wide(and you have set a fixed aspect ration of 4 to 6) then the actual cropped size will be 2x3. And to end up with an actual 4x6 picture you end up with the same resolution as if you used the cropping tool because you will need to resample the image to get it to 4x6. At least with the cropping tool you lose the resolution without having to resample it.

Michael

[jimkovacs]

Michael.

I will get back to you on this, Have to leave for a photo shoot. I have posted an example for you to see the results.

http://www.pixentral.com/show.php?picture=1mf4p5oAQCt51x8y2icXj0YCIs5

[GaryK]

Michael

I'll take a stab at it until Jim comes back.

I'm not sure how he "crops" with the transform, but I'll guess. In your case for example.

Use the marquee tool to select the head. Use proper aspect ratio
Ctrl J to copy the head on its own layer. should still be 300 ppi but tiny.
Now on your new layer hit ctrl T..this should bring up a bounding box
hold the shift key down and drag a corner out until you get to 4x5 or whatever size you have chosen. It should still be 300ppi.


Or just crop with no size or resolution picked.
Then drag out with the transform tool as above.
I could be wrong about his technique and I have never tried to print like this so we will see.:)

[GaryK]

One other thing to keep in mind is that resampling may work for you.
We tend to get stuck on "proper" ways to do things.
The truth being, if you know the caveats and the results are fine, then who cares how you do it.

[jimkovacs]

Michael.
Following is how I crop using Image-Transform-Free Transform



Open your Image

Ctrl J to create a duplicate layer ( to save your original)

Ctrl A to select your entire image

Ctrl T to select Free Transform ( see also under Image Menu- Transform - Free Transform)

Your image will be outlined and will have grab points at the corners/

Move your cursor to a corner, it will change to a diagonal arrow.

Pull each corner, alternating between corners , to enlarge the image portion you wish to keep. ( hold down the shift key as you drag your corners.

When the image is composed the way you want it, just double click within the image, to complete the transformation.

Then ‘save as” to retain you image.

http://www.pixentral.com/show.php?picture=1mf4p5oAQCt51x8y2icXj0YCIs5

I hope this is clear, I use this particular tool quite a lot.

[GaryK]

Jim

How are you getting this to work. Whenever I drag a corner (or any marker) the image just shrinks (or expands). I can't seem to "crop" anything out.

[GaryK]

Nevermind:o :o

[MichaelRS]

Gary-
I don't get the "nevermind". Whenever I drag the corner the whole picture expands. Even when i hold the shift key down.
Michael

[GaryK]

I was dragging in to get to the crop point.(can't do that:D ) If you drag out only the part you want, will show. You hold the shift key to keep the perspective the same. It forces Elements to drag out/in and up/down evenly.

I have a feeling this resamples at some point. I'll have to try some small stuff. But if it works.... great:D :D

[Chuck S.]

Gary, regarding resampling, you're right - resampling can be a good thing, so long as you manage it within reasonable limits. As a general rule, I crop and resize without resampling, but at the very end, when I'm ready to either print or size for web or e-mail use, I'll go back into Image>Size Resize, turn on resample, and adjust either the resolution or the pixel dimensions to reach my goal. Getting to now that Size dialog and what it does is one of the more important learning experiences for Elements (and full Photoshop) users.

Chuck

[MichaelRS]

Gary-
I got it. I agree. I think at some point it has to start resampling to maintain the detail or at some point the quality might deteriorate significantly. I see how it can work if you are doing a little bit of cropping but not if you have a lot of cropping to do. Have you seen that happen Jim?

Michael

[GaryK]

The difficulty I have, is that I really don't print that much. So I can resize all day without resampling and not really see a problem on the screen:rolleyes: