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Old May 12, 2008, 12:42 PM   #1
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I am not totally new here but consider myself an amatuer, have been a member for some time and have posted some pictures and as I have progressed I have a couple of questions.

With my Sony A-700 I have the ability and have shot a couple of RAW format pictures.

The pictures are nice, sharp, very clear, and HUGE file size. Is there really any reason to shoot RAW for the non professional hobby photographer?
My editing software is limited thus far to Picassa, Fastone, and the Sony software that will read the RAW format.

My second question is "What is front or rear focus"? I have seen this referred to in a few posts, but am not sure just what to look for.

I hope this isn't to lengthy and that I am in the right place for posting.
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Old May 12, 2008, 2:47 PM   #2
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Flying Fossil wrote:
I hope this isn't to lengthy and that I am in the right place for posting.
Actually, this particular topic usually is very controversial, and you'll find many long debates of the pros and cons here in a number of forum threads. ;-)

I've moved this post down to our General Q&A Forum, where other forum members will be more likely to see it and respond.

Here's my "lenghty" answer. :-)

This article that explains some of the advantages of shooting in raw. It's not as technical as some (for example, going into the differences between demosaic algorithms used by different converters and more). But, it explains some of the basics:


The type of subjects and the specific characteristics associated with the raw format you shoot will also impact how much benefit you get from using raw, and the raw converter you use will have a big impact on the results. Some are much better than others (demosaic algorithms, highlight recovery, and more).

For example, Adobe Camera Raw is actually a pretty good converter with most raw formats. But, IMO, the newer versions of Photoshop or Lightroom do a horrible job with raw files shot at higher ISO speeds with the Sony A700, even if you set the A700's noise reduction to low and turn it off in Adobe Camera Raw (you'll still get a "watercolor type effect from Adobe's processing, even with the noise reduction sliders turned down).

Third party raw converters tend to do better with the A700 raw files, producing a finer grained noise pattern (versus one that looks like the noise has been smoothed over). For example, Bibble Pro does a great job with your A700's raw files, and I'd use the free Raw Therapee before I'd use Adobe products with A700 raw files (even though Adobe products tend to work well with raw files from most camera models). Note that Adobe products work fine at lower ISO speeds.

The way your specific camera model processes the images can also have a big impact on any benefits you get from raw. Some cameras use a relatively "contrasty" tone curve so that images have more "punch", especially in the entry level category. Each manufacturer tends to take a slightly different approach to image processing. Your A700 is very flexible in this area, thanks to a variety of Dynamic Range optimization settings.

I tend to shoot a lot of high dynamic range scenes (for example, on the river banks in the morning) where despite my best efforts at proper exposure, I may clip both the highlights and shadow areas in the same image. IOW, I've got both underexposed and overexposed areas in the image that are unrecoverable shooting jpeg, even if I reduce my contrast settings in camera (which does help to some extent).

Are these areas important? It depends on the subject. ;-) You may not care if the shadow areas are too dark to retain any detail, and you may not care if some of the brighter areas in the image are too bright to retain any detail. But, then again, you may want to have some of this detail retained.

That's where a good raw converter can come in (and not all raw converters are created equal).

The camera's processing in the A700 is very good, and tends to give better dynamic range compared to most camera models, even with "straight from the camera" jpeg images.

Now, some camera models (for example, Nikon dSLR models) even allow you to load a custom tone curve in camera, versus being limited to the standard contrast settings available. There are companies that even specialize in custom curves for Nikon models and some even provide tools so that you can create your own curves. That way, you can use a tone curve that better matches the conditions you're shooting in up front for the way a camera processes the jpeg images.

If you scroll down to the bride in the wedding dress on this page, you'll see an example of a "White Wedding Curve" developed for Nikon dSLR models (use your mouse to see the difference in highlight detail retained by using it). Shooting raw, you could apply a similar curve to your images if shooting that type of subject, or choose a more or less contrasty curve as desired:


Once you have a curve you like with most raw converters, it's easy to "batch process" your raw files with most. That way, you're not really taking any time to "tweak" images on a case by case basis, while improving the results compared to the camera produced jpeg images. Again, the type of subjects you're shooting, the camera model, and raw converter used can have a big impact on the final images. IOW, it all depends. ;-)

Now, since in camera processors are becoming faster and more sophisticated, we're starting to see models that allow even more control of how noise reduction is handled (like your A700, other than it's still applying some with it's lowest setting

The sophisitication of the demosiaic algorithms being used (by both the camera manufacturers' image processing in camera and in raw conversion software) can also impact the results you get and these algorithms are continuing to improve. I've been particularly impressed with the new AHD based algorithms for a while now, depending on subject type.

Scroll down on this page and you can see links to some comparisions between different raw converters and how they handle different types of detail:


The raw file produced by a given camera model is somewhat unique, and a complicated process is needed to convert the image into a viewable format (and diffferent raw converters will have different approaches to giving you the best image possible, with some of them using better algorithms compared to others for this conversion).

A camera's image processing when shooting jpeg is making decisions that may not always be what you want (and you may not always select the perfect settings for an image).

Manufacturers have to decide on what kind of tone/contrast curves to use to make an image that looks good to most viewers for a given settings combination, and sometimes they use processing that can be a bit too contrasty (causing loss of detail in shadows and highlights), in order to give cameras owners a more "punchy" image straight from the camera.

If you decide to change the image processing with different camera settings (for example, the Dynamic Range options shooting with your A700), you can't "undo" that processing shooting jpeg. If shooting raw, it hasn't been applied yet (so you can try different approaches to the same image).

Ditto for things like sharpening, which is mostly increasing the contrast at color/brightness transitions in an image using edge detection techniques (which can destroy detail if overdone). The same thing is true for how the camera compensates for the temperature of the lighting you're shooting in (your White Balance settings handle that). You can easily modify things like White Balance later if you shoot in raw.

The camera's jpeg processing is also limited by the speed of the cpu/hardware for image processing built into the camera, as to the sophistication of the algorithms used, since they are trying to process images in a split second between shots. I am seeing a trend now towards more sophisiticated image processing in camera though.

Keep in mind that the individual photosites in a sensor are only sensitive to one color each, and with most Bayer Pattern CCD designs, you have twice as many sensitive to green.

The raw conversion algorithms take the values from the red, green, and blue photosites and combine them via sophisticated interpolation techniques so that all 3 colors are stored at each pixel in order to give you a usable/viewable image.

The raw file has not combined the photosites in any way.

That's what the raw conversion process does (or in camera processing if you shoot in jpeg). There are a number of different algorithms used, and some are better than others. You can see some of the common ones discussed here (requires Adobe Acrobat Reader):


Here is another document discussing raw conversion techniques:


When you convert the data from the sensor using a raw converter, you've gone through this demosaic process of combining the values from the red, green and blue sensitive photosites so that red, green and blue are stored at each pixel location. Ditto for shooting in jpeg (the camera is performing the raw conversion if you shoot jpeg) and you can also convert a raw image to jpeg using most raw converters.

Most raw converters are doing some additional processing, too (sharpening, contrast curves, etc.). Ditto for in camera processing (which is doing the raw conversion for you).

Personally, I shoot raw + jpeg almost all the time with my A700.

Most of the time, I'm just fine with the jpeg images for the print/viewing sizes I need. But, for some shots (especially high dynamic range scenes), it's not uncommon for me to run the same image through several diffrerent raw converters if it's an image I may want to print at a larger size, to try and pull the most dynamic range and detail possible from the image before deciding which conversion algorithm works best for the image as a starting point.

RAW also allows you to more easily correct mistakes. You may not always have the luxury of taking test shots and tweaking in camera settings for best results, especially in rapidly changing lighting.

From what I've seen, I can do far better shooting raw at the highest ISO speed settings, with this particular camera model (A700). So, I will probably start using the raw files far more often with it compared to previous cameras I've owned, despite the storage requirements from larger files.

Whether you shoot raw or jpeg is not a "black and white" issue. There are many variables involved, including the camera model, subject type/conditions you're shooting in, raw converter used, purpose for the images including viewing/print size, and more.

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Old May 12, 2008, 2:52 PM   #3
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Here's a recent thread with the same questions you asked about focus type differences:

Lens focusing

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Old May 12, 2008, 3:39 PM   #4
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Jim, thanks for the lengthy but well detailed reply.

I guess the bottom line is depending on your needs, don't fix what ain't broke, LOL.

From my very short and limited time using the A-700 it appears that I will be very satisfied with shooting in jpeg.

I do very little printing and when I do it is in 4x6, 5x7, or 8x10 print sizes.

If I get my exposure right, or even close, and shooting in fine or extra fine, I think this camera will more than meet my requirements.

Now if I could just find a photography club in Orange County, CA.
If anyone knows of one, I would like to hear about it.

Thanks again.
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Old May 12, 2008, 4:38 PM   #5
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Make sure you select a couple of your favorite images from the A700 and have them printed.

I've been absolutely stunned at the image quality the A700 is capable of producing at 8x10" print size with straight from the camera jpeg images except for light cropping. You just can't see the quality this camera is capable of producing on a monitor.

I've uploaded some of my photos to local http://www.walgreens.com and picked them up at the corner store an hour later (walgreens happens to have a store on the corner exiting my subdivision here), and I've been very impressed. You'd likely get similar results from your local walmart, etc. (or any good inkjet printer for that matter).

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Old May 13, 2008, 8:28 AM   #6
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Jim as usual has given a good answer. I also have my camera set to RAW+JPEG unless I need to shoot longish bursts or a large number of photos. One of the main advantages of RAW is that it is easier to fix problems that can come from not having the exposure/white balance/contrast/sharpening/... set right for the shot.

So if you have everything dialed in exactly right, there is lttle reason to use RAW. But if you are like me, it will take several shots and chimping to get things set right. Not enogh time to do that when I grab my camera for a quick shot of the grandkids.
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Old May 13, 2008, 5:15 PM   #7
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I personally never shoot RAW (well RAW+jpg) for anything other then weddings and even so these are only in the church and the formals. The reception etc is just done in jpg. As yet I've not had a need to use a RAW image for printing but nice to know I have them if something is a long way off.
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