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kevinhochen

Another RAW question

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Hello, everyone!

 

I want to make sure I understand a few things about why RAW is important for underwater photography and see it's possible to do the same things with jpeg.

 

RAW is used in underwater work because in post processing:

 

1. Easy white balance manipulation

2. Easy shadows/highlights manipulation

3. Easy exposure control

 

Is that right?

 

Okay, assuming the above is correct, my questions are concerning Photoshop CS2. I'm learning Photoshop CS2 right now and it seems like you can do a few of these things easily with the Jpeg images as well. With CS2...

 

1. There's this white balance slider in the tools that seem to do the same thing

2. There's the shadows/hightlights slider as well that (IMO) works really well

3. It's possible to change exposure with CS2 on jpegs (although definetely a little harder)

 

There's no question that the RAW manipulation is a little easier but it seems like you can do the same manipulation with jpegs in cs2 without too much more complexity. Does anyone have any experience using these photoshop tools with jpeg images? I'm just curious to know if my experience is just a little too naive.

 

I'm asking because my camera works SO much faster shooting jpegs than RAW so I have been missing shots because my camera is "thinking" when I shoot RAW. So, I'm trying to decide if the ease of use post processing is worth the slow lag time underwater.

 

Thanks ahead of time for anyone's help.

 

Kevin

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When you edit in raw, you are editing in 16 bits, in addition changes made in raw cause less degradation of the image. see web site luminous-landscape.com a great source for that , and other photoshop info

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i forgot to add you have a digital negative so to speak to save for future use

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Editing in RAW is Superior to editing a JPG in many ways. But if you cant see the difference then it is not worth the extra memory and time that it takes to shoot raw.

 

99% of digital camera users will find no advantage to raw. Sounds like you have tried both and found the non-raw edits satisfactory. It this is the case, are probably better off shooting jpg until you are unhappy with the quality you get from jpg's.

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Thanks, guys.

 

I have noticed a image degradation when I try to tweak my jpeg images too much in the form of more noise (usually it's not too big of a deal) but I guess I just can't decide which annoys me more - the lost images that come my way underwater when my camera is processing the RAW shot or the more limited lattitude of post processing of the jpeg.

 

I just wanted to make sure that there wasn't anything else that RAW would offer me that jpeg can't. I keep hearing about how adjusting exposure and white balance are why people use RAW the most and as far I am able to tell, I can do the same with jpegs (with some degradation if I need to do it too much).

 

Makes me almost want to buy a housing for my d100 (oh yeah, there's that money thing).

 

Any other thoughts?

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In essence RAW allowsw you to override (to some degree) many of the settings that you had in place on the camera when you took the shot. You can readjust parameters like white balance, adjust contrast, vary exposure slightly and various other things, which you may or may not find useful.

 

Whilst the jpeg appears to allow you to do the same in photoshop, it does so in a way that loses much more information from the digital image file. Whether this is a problem depends on what you use the file for. In many instances you may not notice the lost information, but unexplained posterisation (block colours) or unevenness where the colours should merge smoothly are the sort of problems you may encounter.

 

Personally I ALWAYS shoot raw but there are some, including very experienced photographers, who see no need to do so.

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Yes there are some things that can only be fixed in raw such as chromatic aberrations.

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Hi Kevin,

 

There's a couple of issues with JPEGs as compared to RAW that may affect you.

 

First of all, JPEG images use a "lossy" compression algorithm to keep file sizes down. This is why your camera records JPEGs faster. On the other hand, you do lose a fair amount of detail, even at the highest quality setting. It's possible to verify that by zooming 100% in Photoshop, looking at details of say the eye of a fish, in a RAW and in a JPEG file. The latter will be fuzzy as compared to the former. When shooting blue water, RAW files will also generally produce a much smoother transition from the darker to the lighter hues... Also, JPEG files get worse (coarser details) everytime you open and save them, even if you don't do anything to them per se.

 

Secondly, although you can easily do similar manipulations on JPEGs as you can on RAW files (exposure compensation, colour balance, etc), you're basically modifying something already saved in the file, and computed by the camera. This is very different from the CONVERSION process of the RAW file, where you simply override the camera settings before they are incorporated into the image file. This is demonstrated by the additional noise you mention when you adjust the exposure on the JPEGs.

 

These may or may not affect you in the end, depending on what yuo intend to do with your pictures. If you simply intend to use soft copies (slideshows, web pages, etc), JPEGs are probably fine. If you intend to print your pictures, especially on larger formats, then RAW files converted to TIFFs are very likely to give you much better results.

 

Cheers,

Mathieu

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Thanks for everybody's help on this topic. It is much clearer to me now than before.

 

Just an update - I've been working more and more with my jpeg images and with the manipulation that I do, once the photo gets larger than 4x6 (maybe 5x7), the grain becomes a little bothersome for me. It looks like I'm going to switch to RAW and check it out again.

 

Thanks again!

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Kevin,

 

The "grain" problem you mention after extensive manipulation of jpeg images in PS may be compression artifacts caused by repeatedly saving the image in JPEG format while you're working. There is a loss in image quality every time you do this. If this could be the case, I'd strongly recommend that you always save the image in either TIFF format or as a photoshop file (both are "lossless" formats), and then re-generate appropriately sized JPEG images when you need them.

 

But I'd still urge you to reconsider using RAW whenever possible. There is a lot more room to play with exposure and color balance with an original RAW image.

 

Frogfish (Robert Delfs)

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