Yes Bob, I do use the histogram when post processing my images. I found sometime the computer screen fool you on the image clarity and brightness and when you get it print, it is too dark. My screens are calibrated now so it is not as bad. I started to use the "show" clipping when adjusting the tones, it help to adjust the HDR in images with high contrast. Often the case when photographing trains.
I rarely over expose high contrast images now with the HDR function in my camera. First I was, most of the time, manually reducing the exposure by 0.03 or 0.07 stops, then after many experiment, I now shoot with auto HDR where the camera will under expose automatically images with high contrast. Now the nice thing about this is RAW images do not get affected by the auto HDR, only jpegs (the camera's jpeg engine will automatically adjust the tones and deliver usually a nice image). However, I still prefer to adjust them myself from the RAW file in Lightroom 3. Until recently, this technique to under expose were showing digital noise in the dark area when lighted up but our days, most recent prosumer and professional cameras have an incredible noise control (and it keeps improving), combined with the noise reduction algorithm from Adobe's Lightroom and Photoshop CS5, it is possible in my opinion to get very nice high contrast images with single shots. Simon -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bob Werre Sent: October-25-10 11:24 AM To: [email protected] Cc: shabbona_rr Subject: Re: {S-Scale List} Re: Cameras Roger, Bob, Peter, Simon and anybody who is still interested! First off the histogram is one of the most important things to check when shooting. It is basically a digital map of that image showing the range of shadows and highlites. It comes in real handy when determining what will show properly. For instance if your shooting a dark Pennsy GG-1 near a dark building but you pose a bride dressed in white next to those items you'll want to know what will reproduce in the shot, what will be lost and what will be saved. The usual thing to do is say--Wow that's dark scene, I'll open up a stop or two and shoot--which is what your camera's meter is liable to do. If you do that, you will likely overexposure the bride and the bride's father won't pay you for the shot. The histogram would show a 'spike' where the white would be and a low level of information in the shadows. If you 'open up' too much the brides dress and it's corresponding spike will go beyond the graph--meaning you've lot detail. If you overexpose with digital you'll never recover the image--the color negative that you probably shot back in film days was designed to accept a lot of overexposure and still be printable. With digital, if it's over exposed, better luck next time. When it comes to RAW and working with it, I did a whole day seminar that solved tons of problems, so it does take some learning time and practice time to really understand how it works. One of the advantages of using the Adobe system (Adobe is somewhat like MS--considered pretty close to God himself) is that you do a DNG conversion first--that Digital Negative is becoming the standard of the industry. The Digital Negative Converter is a free download from Adobe I believe. Once you have the negative it goes into the RAW converter. This is where a lot magic happens! You can make adjustments to the RAW file without destroying the original data--impossible in the past! For instance you can crop an image creative a JEPG and email it. A week later you can pick up that same DNG, put in back into the RAW converter create a high end color image in TIFF format to be used for a large poster. So its very much like making several trips to the darkroom or photo lab. So keeping the RAW file or DNG is just like storing a piece of film that can be used over and over again without throwing away data. Peter is incorrect in stating that editing in TIFF retains all the data. If you have to make a radical color change or if you try to save a poor exposed image you will notice a unfortunate change in the histogram (there it is again). Often times when you have to make these changes the histogram will look like a comb. It will have spikes of detail next of open areas; and the slang term is called combing. The open areas contain no data, because you threw it away often resulting in posterization of the image. Now he is correct in stating that you can save the image many times without loss of quality however. My recent updating of computers hopefully will keep me in the loop in processing many large files in rapid fire time span. We did things like arrange hard drives into a RAID, we will take some more and put them into a Drobro. This new box has 'time machine' built into the Snow Leopard--man we come a long way from Mac and cheese! Bob Werre BobWphoto.com On 10/22/10 7:38 PM, shabbona_rr wrote: > > That's one reason I haven't succumbed to DCC. It's one more digitized > headache I can live without, and I would rather use my obviously > limited brain capacity on more productive pursuits. > > Knowing how much time I spend on electronic nincompoopery anyway, I > don't know how some of these people get so much done, yet, I know they > do, because we see the results of their efforts every day. > > The other day, on some website, someone was raving about the value of > histograms in improving photographs, so I looked it up. I might as > well have been up against a ten foot thick glass wall. I could > visually see people happily applying information from histograms to > improve their pictures, but I had no idea what they were doing, or how > they got to the other side of that glass wall! > > On the other hand, I FNF for the day was installing a microswitch to > kill the North Yard storage tracks at Terminal District when the > switch is lined against them. It worked and I feel great. Life is good! > > "S"tring Bob > [Non-text portions of this message have been removed] ------------------------------------ Yahoo! Groups Links ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/S-Scale/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/S-Scale/join (Yahoo! ID required) <*> To change settings via email: [email protected] [email protected] <*> To unsubscribe from this group, send an email to: [email protected] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
