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leighb

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Posts posted by leighb

    Raw vs Jpeg?

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    <blockquote>

    <p>One shot in raw and one shot in jpg.</p>

    </blockquote>

    <p>Perhaps this is a good example of the misunderstandings that are so rampant in this thread.</p>

    <p>There is no such thing as a photo "shot in JPEG". That's physically impossible. It's not how a camera works.</p>

    <p>ALL images are captured as raw data. Period. End of story.</p>

    <p>Software in the camera then transforms the raw data into a JPEG if you told it to do so,<br /> using options and settings stored in the camera.</p>

    <p>This transformation is a completely separate step, no different than doing it on your laptop.</p>

    <p>JPEG is a compression algorithm. Originally it provided only lossy conversion, but a<br /> later revision of the standard provided a lossless option.</p>

    <p>- Leigh</p>

    Raw vs Jpeg?

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    <blockquote>

    <p>What perhaps concerns me is the way raw is quoted as the Holy Grail and beginners are informed that it is the answer to all their problems and it will make them a brilliant photographer.</p>

    </blockquote>

    <p>I've never heard anyone claim that besides you.</p>

    <p>RAW files do not make anyone a better photographer, nor do they make any photograph better.</p>

    <p>A RAW file is simply that... the negative, produced according to the exposure criteria you used.<br /> Nothing more, nothing less.</p>

    <p>And that's the critical factor... nothing less...<br /> That is not true of camera-generated JPEGs.</p>

    <p>- Leigh</p>

    Raw vs Jpeg?

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    <blockquote>

    <p>if one shoots RAW+Jpeg and put the two images side by side on a monitor would the look different <em>before retouching?</em></p>

    </blockquote>

    <p>They might. It depends on the camera settings.</p>

    <p>You're proceeding from a false assumption...<br /> There is no such thing as a camera-generated JPEG "before retouching". Such a file does not exist.<br /> The retouching is done in the camera as it translates the raw sensor information into a JPEG file.</p>

    <p>A lot of the misinformation in this thread is the result of people not understanding<br /> that a digital camera IS a computer. It has all the same components as your laptop.</p>

    <p>- Leigh</p>

    Too Many Lenses?...

    in Large Format

    Posted

    <p>A lens is a tool (assuming you take pictures with them).</p>

    <p>Any craftsman will tell you that the best possible results are achieved when you use the right tool for the job.</p>

    <p>I shot slides for many decades, both 35mm and MF, so my lens sets in both formats are pretty complete.</p>

    <p>My LF kits are set up similarly, with 14 different lenses in the 4x5 kit. I shoot chromes in 4x5 and 8x10 also.</p>

    <p>- Leigh</p>

     

    measuring EFL

    in Large Format

    Posted

    <p>To determine the optical focal length you must take two measurements:<br /> 1) The distance from the back edge of the lens barrel to the image when focused at infinity.<br /> 2) The distance from the back edge to the image when set to 1:1 reproduction ratio.</p>

    <p>The difference between 1 and 2 is the optical focal length of the lens.</p>

    <p>The optical design of the lens has absolutely no bearing on these calculations.</p>

    <p>The numeric aperture is the ratio of the optical focal length to the diameter of the entrance pupil.</p>

    <p>- Leigh</p>

    inserting quotes in response box

    in PhotoNet Site Help

    Posted

    <blockquote>

    <p>You mean like this?</p>

    </blockquote>

    <p>The editor on this site is a bit weird.</p>

    <p>Go into the response box and type a single carriage return.<br /> Then use the up arrow to get back to the beginning and click on the large double quotation mark in the toolbar.</p>

    <p>Now your cursor is inside the shaded box, although the only indication is that the cursor moves to the right by a few spaces. Anything you type will be inside the box. You can also paste text from the clipboard.</p>

    <p>When you're done with that, press the down arrow key to exit the shaded box and return to the normal text entry section.</p>

    <p>Weird, isn't it. No, one ? is NOT ? enough ?<br /> (That's a rant because the damned editor said one question mark was sufficient and wouldn't let me insert three.)</p>

    <p>- Leigh</p>

    Raw vs Jpeg?

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    <p>Well, JC,</p>

    <p>If a camera does not use the settings and options as currently set...</p>

    <p>What settings and options does it use???</p>

    <p>As to the "RAW fanatics" label, I am nothing of the sort. I'm an engineer.<br /> I made a simple statement that a RAW file contains the unaltered sensor data.<br /> That is an absolutely accurate description of the RAW file content, not based on any opinion whatsoever.</p>

    <p>Are you claiming that the statement is incorrect?</p>

    <p>And what exactly makes a RAW file "cumbersome"?</p>

    <p>People commonly fear that which they don't understand. It's human nature.</p>

    <p>- Leigh</p>

    using different flashes in tandem from one receiver

    in Lighting Equipment

    Posted

    <p>It's not a good idea to connect multiple strobes to a common trigger circuit.</p>

    <p>If the trigger circuit voltages are different (almost certainly true), current will flow<br /> between the strobes that may cause false triggering or damage the equipment.</p>

    <p>The difference need not be large for this problem to occur. <br>

    A small fraction of a volt will cause current to flow.</p>

    <p>Use optical slaves instead and you'll have no problems.</p>

    <p>- Leigh</p>

    Raw vs Jpeg?

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    <p>There's no such thing as an "excuse" for using raw, any more than there's an<br>

    "excuse" for shooting film.</p>

    <p>Raw is a way to capture and retain all information available from the subject.<br>

    This is the same thing that happens with film. </p>

    <p>Creating JPEGs in camera is analogous to always shooting through a cc filter. <br>

    It might be right for a given situation or it might not.</p>

    <p>It goes without saying that any exposure should be correct. <br>

    If you screw up that step there's no way to correct it in a computer.</p>

    <p>- Leigh</p>

     

    Raw vs Jpeg?

    in The Digital Darkroom: Process, Technique & Printing

    Posted

    <blockquote>

    <p>my photo-retouching artist told me that there were no differences of quality between High Res Jpeg & Raw files...</p>

    </blockquote>

    <p>That's not true.</p>

    <p>A camera-generated JPEG will use whatever options and settings are set in the camera.<br>

    They may or may not be correct. If they're wrong, it's difficult to correct the image.</p>

    <p>Shoot raw, or if the client insists shoot both and give them the JPEGs. <br>

    Then you have the option to generate new JPEGs if the client decides there's a problem<br>

    with WB or color or whatever.</p>

    <p>- Leigh</p>

     

    battery/memory swap causes grief??? D7000

    in Nikon

    Posted

    <p>Prove it. The display may go off, but that's meaningless.</p>

    <p>Unless you have an oscilloscope monitoring the CPU clock line you <strong>do not</strong> know what it's doing.</p>

    <p>The point of my previous post was that you should not run your mouth when you do not know<br /> what you're talking about. In this case you clearly do not.</p>

    <p>- Leigh</p>

    battery/memory swap causes grief??? D7000

    in Nikon

    Posted

    <blockquote>

    <p>Obviously the camera would be forced to "switch off" when you take out the battery.</p>

    </blockquote>

    <p>Shun,</p>

    <p>There's no reason to assume the camera would turn off if you removed the battery.<br>

    In fact, with modern electronic equipment that is definitely NOT the case. </p>

    <p>Battery-operated products have hold-up capacitors that power the circuitry when<br>

    the battery is removed, for a short period of time, but not forever.</p>

    <p>Your experiments are meaningless. Without access to the source code for the software<br>

    that's running in the camera there's no way to determine what it might do.</p>

    <p>- Leigh</p>

     

    battery/memory swap causes grief??? D7000

    in Nikon

    Posted

    <blockquote>

    <p>Canon manuals say this also. However, I have never worked with any other pro that does it, I have never done it in almost ten years of shooting digital, and I have never seen it cause a problem. I suspect it's just there for legal purposes...</p>

    </blockquote>

    <p>No, Jeff.</p>

    <p>There's a very sound technical reason for turning the camera off and back on.</p>

    <p>The CPU needs to go through its power-up initialization to properly characterize the memory and<br>

    options as configured at that time.</p>

    <p>If you make a change on the fly and don't go through that step, the CPU may think the<br>

    configuration differs from its true state, and the results can be unpredictable.</p>

    <p>I've designed dozens of such pieces of equipment, and I guarantee you that most<br>

    designs cannot be relied on to properly re-configure while powered up.</p>

    <p>I really hate it when people make assumptions about manufacturer's instructions<br>

    without knowing a damned thing about the underlying technology.<br>

    <br />- Leigh</p>

     

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