Same Quality?

[JR92]

I have my D60 set in large format for my picture size. On a 128mb card it allows me to take roughly 86 pictures. If I set the camera setting to small format will it take away any quality of the picture or will it just make it smaller? To me quality is much more important than quanity.
JR92

[Roger_Cavanagh]

JR92 wrote:
To me quality is much more important than quanity.
JR92

In that case, you should buy a larger CF card and shoot raw format. :)

Cheers,

[jd_D60]

Would it be possible for someone to explain in simple terms what the image size/settings are good for.

Also when using RAW (or others for that matter) how should you handle the image, I use Photoshop 7 to edit but want to make sure any changes I make retain quality.

FWIW I also take most of my stuff in large/fine (40 ish to a 128Mb) and at A4 the quality looks pretty good.

One final question I have noticed printing this quality to A4 leave my Epson Stylus Photo 870 running short of juice fairly quickley, anyone no what optimum printing settings would print acceptable results and offer more than about 5 prints per colour cartridge.

john

[gorham]

I'd be interested in a good description of the differences in settings also. So far I mostly shoot in fine JPG. I don't need to print larger than 8x10 and, actually, a lot of my regular stuff is web work anyway.

I did play with a few raw images when I first got my D60 but didn't feel the extra conversion work was worth the return for my uses (although I did get a grand photo of my kitten yawning - all yawn, very little kitten). I would like to know more about it for freelance or pleasure work. I've only used BreezeBrowser to convert so my experience is both limited and begging for more information. I have (but have not had time to learn much about) PhotoShop 7. I have the classroom in a book but have found osmosis doesn't work wonderfully well; did I mention the time factor? I also have several actions but haven't tried to use any yet so don't know much about those either. Like whether that comment was germain to this thread. :)

Anyway, thanks to you who regularly use and edit .crw files for your expertise.

Gorham.

[Dans_D60]

Good digital cameras like the Canon D60 will expose several million individual pixels every time the shutter is released. Also, current state-of-the-art in digital cameras only “see” in shades of black and white. So the sensors have colored filters to decode intensity for each of the primary colors. Typically three or four color filters are used. By capturing each color’s intensity, color images can be reproduced on screens or in print. So resolution basically is the combination of the total sensor pixels plus the dynamic range for each color. Since we are talking digital here, the number of intensity levels is expressed in “bits”. More bits mean more color levels. For example, 8 bits will permit 256 different levels of intensity. Remember at least three color filters are required to properly reconstruct the image. Simple example; let’s say we have a 3 million pixel sensor with three filters (1 million red, 1 million green, 1 million blue). Now add 10 bits of intensity level for each color. 3 million X 10 = 30 million “bits” for each shot. In this example each image is about 4 megabytes in size! A little large for a 3 mega pixel camera!

To overcome image size issues with good quality digital cameras, several different compression algorithms are used to reduce the image size before uploading into the computer. There are two basic types of compression algorithms; 1) Lossless compression and 2) Lossy compression. Lossless compression means none of the original image parameters are lost. Lossy compression means some data and data parameters are lost and cannot be recovered. However, these lossy compression algorithms permit much higher compression with much smaller image files. Canon uses two compression algorithms 1) Lossy compression is accomplished with JPEG (Joint Photographic Experts Group) algorithm. JPEG allows compression with a lot of image quality flexibly. Lower quality means smaller file size by using more aggressive compression. Again, there is no going back! Lossless compression in Canon cameras is accomplished with “RAW” files. These files are not really “raw”, they are compressed, but the algorithm will retain all image data including parameters like contrast levels, white balance, and so on. Raw files give you the flexibility to change the white balance as many times as you want after the picture is taken. I use this feature a lot. When I take studio photos with artificial lighting, white balance is accomplished in the computer. I never worry about the color temperature of the lighting being used for the shot.

Certain brightness levels, color balance, and other parameters can be accomplished with JPEG files and good photo software like Photoshop. But, these adjustments are no where near as flexible as with RAW images. Problems with RAW images; 1) size, 2) they must be converted to a “standard” file format like JPEG or TIFF before other applications such as Photoshop can use them.

Hope this helps! … Dan

[madhg]

Thanks for this very clear exposition. Just one question:

Dans_D60 wrote:
....
Certain brightness levels, color balance, and other parameters can be accomplished with JPEG files and good photo software like Photoshop. But, these adjustments are no where near as flexible as with RAW images.


Could you explain this? Most photo-editing software will adjust brightness, contrast, colour balance etc. etc. on JPGs. What are the limitations of JPG compared with RAW in this respect?

[Roger_Cavanagh]

madhg wrote:
Thanks for this very clear exposition. Just one question:

Could you explain this? Most photo-editing software will adjust brightness, contrast, colour balance etc. etc. on JPGs. What are the limitations of JPG compared with RAW in this respect?

The limitation of JPG is that it is a compressed format. When you take JPG images with the D30/60, you are throwing away some image data straight away.

Raw images (especially linear) give the best picture data for post-processing. You can avoid using in-camera processing for sharpness, contrast and saturation. As Dan pointed out Photoshop has much better options for working with this stuff.

Working with raw images does take more time than JPG, but if you set up a good workflow, it shouldn't take any more of your time. You just get the PC started and go and take some more pictures. :)

The D30/60 takes 12-bit images (in each channel). JPG uses only 8-bits. This translates to 4096 levels per colour compared to 256. I think this is too much data to throw away before you even get to see the image.

Regards,

[madhg]

Roger, I looked at your web site, and got a better understanding of why 16 bits is better than 8 bits (the JPG standard). This article was helpful:

http://www.creativepro.com/story/feature/7627.html

In a nutshell: when you adjust levels/contrast/colour of 8-bit images, you destroy some of the detailed level information and may end up with banding or lost colour details (blown highlights). Much less likely with 16-bit tiffs.

On the other hand, apparently Photoshop isn't entirely geared up for 16-bit images - some tools work, others don't, according to http://www.creativepro.com/story/feature/16097.html

David Griffel

[gorham]

*Excellent* information here, thanks. Which, of course, brings more questions, as I guess it should.
Working with raw images does take more time than JPG, but if you set up a good workflo
I've got a decent, if a bit cumbersome, workflow set for working with fine .jpg all the way from the inital photoshoot to my redundant x 2 backups. I know each of us has an individual comfort level with workflows and I know it's been hashed to death before but if a couple of you could outline your workflows with .crw, it would give me an insight as to where to plug certain activities into my flow.

Also, if one of you could summarize what I might be looking for re: the storage/numbering problems when shooting in RAW. I've read them as they were posted but it was one of those "this doesn't apply to me so I'm not going to pay a lot of attention" thingies.

I'm a university sports photographer and our seasons are coming up quickly but what I'll plan to do is go shoot some practices in .crw and see if I can manage the volume and timeframe. I see now the quality and editing flexibility will be hugely improved but I also have to see if I simply have the time to work with it.

Thanks, all of you for asking good questions, answering in completely and understandably.

Gorham.

[madhg]

gorham wrote:
I know it's been hashed to death before but if a couple of you could outline your workflows with .crw, it would give me an insight as to where to plug certain activities

http://home.austin.rr.com/g2darkroom/Linear_Workflow.htm

A good clear description.

[Roger_Cavanagh]

Gorham,

I've posted a description of my workflow here: http://www.rogercavanagh.com/library/t11_workflow.htm.

Regards,

[gorham]

Thank you both. That's *exactly* what I was looking for! :)

G.