askMarv™ Your Photographic Questions Answered Archive

The askMarv™ Archive is a service provided by Imagedancer compiling past questions and answers. Use the links provided to submit your photographically related questions or comments and Marv will personally address each with relevant responses. No personal information will ever be shared.

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Marv,

A contest rule allows for 'burning, dodging and color correction". What are burning and dodging?

Thank you,
Submitted by P.R. -- SC
9-8-07

Dear P.R. from SC:

Dodging and Burning Basics

In the traditional darkroom, dodging refers to the process of shielding an area on a print from receiving light during print exposure. Conversely, burning refers to allowing more or additional light to expose a particular area of a print during the print exposure.

These techniques allow lightening or darkening selected areas of a print beyond what a ‘straight’ or uniformly printed image would reveal in a final print. This allows lightening areas of an image where the negative is too bright or unsaturated to bring out shadow detail; or darkening areas of an image where the negative is too dark or dense requiring additional exposure to bring out highlight detail. As you might guess, technique is the key to creating pleasing results so practice, practice, practice.

These techniques apply mostly to traditional wet darkroom black and white printing. Wet darkroom color printing does not allow as much flexibility in dodging and burning because of limitation is the color materials and process.

In the digital, virtual darkroom, similar processes are possible with effective results possible with both black and white as well as color images. Color digital printing can often benefit from ‘spot’ lightening or darkening (dodging or burning) beyond what was possible with traditional wet darkroom color printing. This is one of the clear advantages of the virtual darkroom for color work.

– askMarv™

Marv,

I just got my first single-lens reflex digital camera and was wondering how I can use the graph of the image. What is it and is there a simple way I can use it for taking better pictures?

Thank you,
Submitted by A.M -- CA
3-1-07

A.M. from CA:

The graph is call a histogram. It forms a graphical representation, a simple graph, of the brightness levels in an image from darkest (on the left side of the graph) to the brightest (on the right side of the graph). The vertical axis (the height of points on the graph) shows how much of the image is found at any particular brightness level.

Using the Histogram
The histogram really comes into its own if there are no flashing highlights. If the image on the LCD display is clearly too dark, retake the picture with an increased exposure, repeating until you find the maximum you can give and keep your highlights sweet.

The histogram is a bar chart of sensor cell densities in the image, generally corresponding to the minimum exposure at the left and the maximum at the right. Histogram shapes depend on the tonal distribution within each image, but ideally they should come down to zero at or near each end of the scale.

If there is a large empty area at the right of the scale, then you should increase exposure, as this will decrease noise in the image and normally improve tones. However, keep an eye on the actual subject values on the screen, and don't let the highlights get too light. So long as the highlights are right and the LCD image looks fine, there is no need to worry about empty areas at the shadow end.

If your histogram has non-zero values at the high (right) end, then you need to reduce exposure. Non-zero values at the low end mean you are underexposing. With non-zero values at both ends you have a subject with too much contrast for the sensor to cope with, and you will either have to add fill-in lighting to reduce the lighting contrast or reduce exposure and accept a loss of detail in the shadows. For much normal photography, an exposure correction of -2/3 stop is a good starting point, though I find values from about +1 to -2 are occasionally indicated. When working under pressure it isn't possible to check every shot, but a single setting generally works unless the lighting changes.

– askMarv™

Marv,

I never use any filters with my digital camera, but I often find that my pictures have washed out skies and flat look to color. A friend swears by his polarizing filter. He uses it to make the sky in his pictures darker, but they look fake to me. His pictures also have brighter colors than mine. What's up with polarizers?

Cheers,
Submitted by B.D. -- OK
9-20-06

B.D. from OK:

In practice, there are two different types of polarizers: the older linear and the newer circular. The circular polarizer is required with camera systems where the built-in light measuring system uses light that has passed through the mirror via a beam splitter. In this case the light is already partially polarized, which is the case on all AF-cameras (auto-focus). Using linear polarizing filters on these types of cameras cause incorrect focusing and exposure measurements. It is recommend that you use a circular polarizer with all digital and AF cameras. Actually, I cannot think of a reason to use the older linear type polarizer any longer.

Exposure Compensation
As with any dense filter, some light is lost reaching the film or digital sensor as it passes through the filter. Every filter is assigned a filter factor which indicates how much exposure increase is needed to compensate for that particular filters density. The polarizer has a factor of approximately 3.4, which translates to 1½ stops. The best advice is to determine correct exposure and then add an additional 1.5 exposure units for the filters density. Many metering systems give incorrect exposure data when metering through a filter, due to its color or polarizing angle. Mounting a polarizer onto the lens and rotating it can easily show this effect. Often the exposure data will change with rotation, which would give an incorrect exposure. The density for the filter remained constant therefore any exposure variations should not be implemented. The same advice is given for those using a medium or large format camera and a hand held meter, determine correct exposure then add the 1½ stops necessary for the filter density then polarize as desired.

For more about polarizing filters, visit my Polarizing Filter Page, Click Here.

The last thing I can say is if you don’t have a polarizing filter, stop reading this and go get one!
– askMarv™

Hi Marv,

I recently bought my first digital SLR camera and need a new tripod. My old one is quite heavy and has become shaky, even with the center column braces. What do you recommend for choosing a tripod for average picture taking.

Sincerely,
Submitted by D.J. -- CA
3-2-06

D.J. from CA:

Choosing a Tripod
Ask any professional photographer the one thing they love the most and you may be surprised at how many point to their tripod.

Tripods no longer need be the unwieldy, heavy contraption you remember your dad lugging around when you were a kid. New materials and design offer lighter weight and smoother, easier setup.

What to Look for in a Tripod
The following features come in handy and are ordered in rank of importance, at least in my estimation.

Stability
First and last, you need your three-legged friend to do the job for you. You need it to be stable. This out ways cost, weight, etc. Stability comes most directly from mass or weight. Materials, design and quality can easily double the stability of your three legged wonder. One new ceramic material being touted for being particularly solid and ‘un-springy’ has been developed by Gitzo, the French manufacture of quality tripods. The company calls their new line Basalt tripods with the new ceramic legs.

Never choose a tripod that ‘rattles’ or has loose fittings. Such faulty manufacturing flaws actually make a tripod shaky.

Quick Release
Always a good feature, this allows you to quickly mount your camera body on the tripod or to whip it off in a hurry.

Example: You are driving along and you spot a spotted owl on a stop sign, eyeing a snake sunbathing on the shoulder. You stop and (if she hasn't flown already) you set up. Having to screw your camera on will usually keep you from doing it. You will most likely skip this step, lean against something, and do your best (we are only human). You get your pictures back and, guess what, your low ISO setting has caused the camera-shake to be all too noticeable. If you had been able to slap the camera on the tripod in a jiffy, you might have got that shot and won local the contest.

As Much Height As Your Need
Don't rely on the extension pole in the middle on the tripod. If you will be shooting at eye-level often, get a tripod that extends the your eye-level.

Compactness
On the road? Or backpacking? Or, worst of all, flying with only carry-on (if you can help it)? A tripod that folds into a tight package will keep it convenient to use, and we all know how much of a part convenience plays in the actual-usage-to-closet-storage ratio.

Controls That Make Sense to You
What do you feel more comfortable with - the video game controls of a joystick or the level-headed 3-way pan-tilt head? Pick controls that are easy to change in a moment, where you don't have to look at what you are doing, and that seem intuitive to you.

Now that you know what to look for, go pick one out. If the thought of selecting a big professional tripod is overwhelming, at least dip your toes in with a beginner's version. Either way, you will be glad you did.

Here are some links to a couple of well respected tripod manufactures you may find useful for reference: Gitzo • Bogen
– askMarv™

Marv,

My daughter is getting married and was planning to wear a long veil with rhinestones delicately placed all over the veil. I had read t

o be careful of what you have on a veil due to when taking pictures the veil could appear to have black dots on it. The rhinestones are glued on and the back of each rhinestone is flat and black in color. The bridal salon never had heard of this. What is your advise?

Thanks for taking the time to answer my question.

Submitted by G.M. -- MI
1-20-06

G.M. from Mi:
Thanks for asking about lighting a tricky subject.

I assume that your daughter's dress and veil are white. The appearance of the dress/veil and each rhinestone will depend on how each is illuminated.

Without knowing the size and number of rhinestones, I will try to make a few assumptions and general lighting considerations.

The problem is somewhat like lighting an egg. Diffuse light or strong light, each creates a different effect. Both can be effective.

I believe there are two subject lighting considerations:
Overall appearance
Specific detail appearance (I will cover this in the full discussion)
In the first instance, which will be the one important in featuring the brides full-length or facial close-up appearance minimizes the significance of small elements in the picture, i.e., the rhinestones or skin blemishes. Even the stones that catch the light because of favorable positioning relative to the light source and the camera or viewer, their impact in the photograph will be very subtle. Like wise, the stones that are not oriented to catch the light in such a way as to reflect a sparkle toward the camera or viewer will be of little effect. In the event that you have some close-ups of your daughters face, which will also challenge the makeup artist to cover skin blemishes, the stones, if they show at all will not likely produce a 'black' spot that is any more distracting to the picture than those that catch the light and reflect a bright twinkle to the camera/viewer. Even if you used clear glass, the orientation of each piece of glass would render the individual pieces differently.

If a diffuse light source is used such as large light boxes or umbrellas, which cast a very soft light over a fairly broad area, much like the effect from a sunlit thin overcast day, light will come from many directions for a low contrast, soft or open shadow effect. You may find that this will subdue the glint from the stones but also avoid heavy shadows in the dress and the veil for a gentle overall effect.

If more direct lighting is used, shadows will be more dramatic and the potential twinkle from the rhinestones stronger and shadows cast by folds or the individual stones as well. Stronger shadows offer more bold effect with more power because the contrast between light and dark, shadow and highlight, will be more stark. Stronger direct lighting also brings out skin texture, lip detail, eye detail, etc. which may require more attention to makeup artistry. All of this is to bring out the loveliness of your daughters radiance and personality.

Balancing highlight and shadow controls mood whether under diffuse lighting conditions or direct light. It would seem that overall effect will carry the day, realizing that each rhinestone will not have perfect illumination to twinkle from any given viewing perspective, i.e., camera and lighting angle.

It would seem that featuring your daughter in each picture is the important thing. While her dress and veil are important elements, everything in the picture should be about her. To my mind, the dress and veil are part of the frame to emphasize your daughters beauty and personality.

You may find, and your daughter and her groom may find, that they will want a variety of moods expressed in their pictures. Some soft dreamy romantic portraits may be part of the mix and some more strongly lit pictures to express strong feelings my also be appropriate.

The human eye is an amazing thing. Coupled with the filter in our brains, the eye has a great capacity to concentrate on details or filter them out. It sounds like you and your daughter, along with her groom are about to enjoy one of the precious experiences in life. I hope that the experience in preparation balances details and expectations appropriately and with good heart. Not every element in a photograph can be ideally controlled, particularly with a large number of variables, like rhinestones. Photography is an art of visual compromises. Care in lighting can help create conditions for great pictures to refresh the memory of a joyous time. I would encourage you to ask your photographer for a variety of lighting setups so you will have a broad selection of images to choose from in the end. This may require more investment, but may give you the control you seek in selecting favorite pictures of your daughter's wedding.

I hope this helps.

If you have any other questions or comments please let me know.

Have a wonderful time and enjoy the wedding and all that goes with it. – askMarv™

Marv,

How do I know if my flash is strong enough to freeze motion and keep the image in focus? Should I rely on setting the camera manually to 5.6 and 1/60 or should I put it in program mode and let the flash coordinate with my camera settings? I've had a problem with dark or out of focus images using my Canon 20D with its compatible flash, the 580EX.

Thank you,
Submitted by B.T. - ME
12-2-05

B.T. from ME:
Flash duration of a Canon speedlite changes with subject distance from the light source. At close distance the flash duration may only be 1/50,000 of a second. This will show a stream of water from your faucet as though it were frozen in several disconnected packets of water. A substantially longer exposure would render streaks of motion as the water flowed. Up close you can stop almost anything. As distance increases the duration also increases to a maximum of, something on the order of 1/300 of a second. You will have to gauge if this is enough to stop the action at hand and is enough illumination for proper exposure at the given distance for the ISO (sensitivity) setting of your system.

Many cameras will deliver the flash and also provide a shutter speed that is long enough to provide proper exposure, if set in one of the auto modes. The results are an image with stopped action from the flash with the secondary exposure from the longer shutter speed providing a secondary image with blur.

If you don't like the secondary blur after the sharp image, here are a couple of things to try. 1- manually set the shutter speed to the highest sync shutter speed the camera will allow. This is generally 1/125 or 1/250. That will help eliminate the secondary ghost blur. 2-check the flash illumination to see if it will provide sufficient light for the distance by pressing the open flash button at the base of the flash unit. Mine is labeled "pilot". If there is enough light for a stop action picture the light will show green. Go ahead and shoot, all will be well. If there is not enough light it will show red. Change the ISO to a higher number - more sensitive - (say from 100 to 400) and check-flash again. 3- open to a larger f/stop. This may provide enough exposure, but will decrease the depth of field. This may not allow the entire subject to remain in sharp focus. 4- Move closer to the subject, if possible, and use a wide angle lens. The wide angle will provide greater depth of field (field of sharp focus) and the closer distance will increase the effective amount of light from the flash, hopefully allowing for a good exposure. – askMarv™

Marv,

I am new to the digital photography world. What are the advantages & disadvantages of micro drives and compact flash cards for use in digital photography? It seems that micro drives offer more storage for less expense.

Thanks
submitted by: E. K. - NV
10-4-05

E.K. in NV:
You are correct, Microdrives do offer more megabytes per dollar. Their technology is a miniature hard drive, just like the one in your computer. It is a very small spinning magnetic platter with a floating (on the air current) read head. Tried and proven technology.

The Compact Flash technology is a solid state memory system with NO moving parts. This technology is becoming less expensive, but demand rules price.

The disadvantage (in its way) goes to the Microdrive for being less robust, because of the moving parts. I have dropped one from my desk to the floor - that finished it off, literally. The platter support spindle is not captured or secure. It does not ride in a set of bearings like their bigger cousins. After my disassembly I found that the spindle rides in a dimple in the top and bottom support cap with a small drop of lubricant. This is a fragile system vulnerable to shock.

CF cards, on the other hand, won't fail in that way. Microdrives require a cushion of air for the read head to float upon. They have a small hole in the back wall (you can see it) to breath. That can become plugged if you put a drive in a pocket without first putting it in its plastic case. That can cause drive failure. It also allows moisture or fine dust to enter (a little bit doesn't hurt), drop it in your coke and it will fail. Solid state CF cards are sealed. I don't recommend a coke bath, but the BBC published a report about an accidental dunking that did not hamper the operation of their CF cards. Because the Microdrive needs air they do not work above 10,000 feet of altitude, because the air is too thin. They will fail. They are also temperature sensitive to a much greater degree.

I have not disposed of my Microdrives, but I have not replaced them with new Microdrives. After having lost data on a 1GB Micro I have switched to CF cards. The eight CF cards I have are 1GB units. I am afraid to put too many eggs in one basket, if you know what I mean.

It boils down to: cost vs. storage space vs. reliability. – askMarv™

Hello Marv,

How would recommend photographing large photographs that are behind glass and framed? I don't want any reflections to show.

Thanks,
submitted by: S.T. - WY
08/12/2005

S.T. in WY

It sounds like you are talking about pretty straight forward copy work. It can be done from a tripod, camera facing forward & perpendicular to the object to be copied OR straight downward using a copy stand with the work laid below the lens. It is important to keep the camera and work square and parallel with each other. Any amount of twist or angle will produce a skewed final picture. It is also best to use a true Macro (flat field lens) to avoid distortion and allow you to get close enough. OR use a longer than normal lens and an extension tube to get close, if necessary.

The second thing to be aware of is white balance. If you are using the typical tungsten copy lights, use tungsten film OR set the tungsten WB setting on your digital camera. Flash or daylight will require their respective settings.

Shut off or eliminate all other light sources to eliminate other glare and eliminate reflections from the camera onto the copied work using a black screen with only a hole for the lens. It is also easier to control reflections of the camera in the subject glass if the camera is at a greater distance from the work.

Angle of the light to artwork being copied is important, so generally we use controllable tungsten lights. Lights should be set at a 45 degree angle to the work. This will help eliminate glare on the picture frame glass. If there is remaining glare use an adjustable polarizing filter over each light source to completely eliminate it by adjusting (rotating) the polarizers while viewing through the camera until any reflections on the artwork are eliminated.

Make an incident reading of the light quantity at the art work with a hand held meter OR a reflected reading from the camera to a gray card at the artwork plane. Set the camera for at least f/11 with a reciprocal shutter speed (then do not make any other adjustments) and shoot the artwork. – askMarv™

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