Do Megapixels Matter?

Apr 172011
 
 April 17, 2011  Posted by Habenero at 10:03 pm General Notice, Photography , , , , , ,  No Responses »

Digital cameras are constantly evolving.  One of the most prevalent ways the public sees is through the megapixel count published by the camera manufacturers.  Is a 6Mp camera good enough for you or do you need something considerably larger?  The correct answer is, “It depends”!  If you are shooting primarily for web use and have no intention of creating an image that is going to be printed larger than 4″ X 6″, you can probably get by with nothing more than the same number of pixels found on a high end cellphone (about 4Mp).  The problem is that cellphone cameras do not have interchangeable lenses and are mainly good only for fairly short distances. If you never print larger than 8″ X 12″, or shoot mostly jpeg files for web or newspaper publishing, a 6Mp camera will do.

As with film cameras, serious photographers are not satisfied with something that is adequate for the average user or the press.  There are “gadget freaks” who buy only high end gear because they have the mistaken idea that owning a high end camera makes them a better photographer.  Camera manufacturers take these things into consideration and create new cameras for these people and the race for the highest pixel count is one of the ways we get to see results.

The biggest advantage of a high pixel count is resolving power.  The higher the pixel count, the finer the detail the camera will be able to record.  Of course the disadvantage of very high resolution camera bodies is that if your lens is not also of high quality, you may not be able to take advantage of the better sensor.  If you have higher resolving power, you give yourself room to crop out more of the image and still retain enough detail to make a decent print.

The most important factors in deciding how many mega pixels you need should be how large of a print do you plan to make and how much cropping do you plan to do to the image before you make that print!

Has Your Camera Gear Gotten Too Heavy?

Apr 032011
 
 April 3, 2011  Posted by Habenero at 4:31 pm General Notice, Photography , , , , ,  No Responses »

When shooting images in the field, the control freak in me insists upon taking as much equipment as I can just in case.  I am one of those guys that has come to the conclusion that if I have all my lenses and flashes at my disposal I will be sure to have the right lens for anything I want to shoot.  At least I used to be.  The biggest danger in thinking that way is that invariably, thanks to Murphy, the wrong lens will be on the camera for one of those once in a lifetime shots.  Is there a solution, no.  Does it mean one has to carry each lens on its own camera, no.  Why is that not a solution, because if you have each lens on its own body, at the precise moment you need a particular lens, it will not be the one in our hand.

Aside from the selection of the wrong lens at the right time, weight becomes an issue.  My camera gear without the tripods and extra flashes weighs in at over 25 pounds!  Even using the best possible distribution of the weight to enable the most flexibility and ease of access, that weight has contributed to the deterioration of my knees.  Back pain is another insidiously rampant problem for some photographers.  I guess I am lucky that only my knees are hurting, because at least I do get considerable relief when my Synvisc injections take hold.  Unfortunately for me, that leaves me with the ability to carry equipment safely for only 2 to 2.5 months out of every 6.  Or to essentially risk overdosing on pain killers just to be able to get the equipment to the shooting location (not a viable option, nor one I would recommend, long time use is also not good).

By careful planning, pain can be avoided or eased.  Careful research into where I am going when planning a vacation can eliminate the need to take the majority of my equipment.  If shooting models, Rarely will I need to carry my longest or shortest lenses (but increases the likelihood I will need extra flashes batteries and reflectors for a net increase in weight, but spread among other bags that someone else may have to carry).  Bags are out there that can handle your equipment and provide a platform to sit on if needed (http://www.walkinbag.com/ and http://www.seatkase.com/ come to mind).  Putting wheels under your equipment makes traveling much easier and always having a place to sit enables you to become less fatigued.  It is important to find a solution to the weight burden your equipment places on you so that you can enjoy taking photographs as long as possible!

Lens Repair

Jun 132010
 
 June 13, 2010  Posted by Habenero at 8:58 pm General Notice , , , ,  No Responses »

There are no user serviceable parts for most good lenses. Does this mean one should avoid taking their lenses apart if they break down? Short answer is YES. The longer answer is it depends upon your background, the tools you have on hand, your comfort zone when it comes to working with parts with very small springs, switches and screws, and the area in which you can work. That said, I do not recommend you take your lenses apart unless they are completely out of warranty, and you have already committed to buying a replacement.

That said, I just opened up a Sigma 28-105 with a Canon mount (it is not my lens, but the owner had nothing to lose by anything I did to it) that had stopped working. It would focus and zoom, but the iris was stuck somewhere around f/11.  The problem manifested itself after prolonged exposure to the Arizona torture chamber known as a car trunk.   There are only a few reasons an iris that is electronically controlled will stop working.

  • The contacts to the camera are too dirty, not this time.
  • The gears that couple the motor to the iris have lost teeth, not in this case.
  • The iris is jammed, it works just fine manually.
  • The ribbon cable that provides power to the stepper motor, BINGO!

Now I can only hope to remember where all the parts go by the time I find a replacement for the ribbon cable.

Camera Controls (Part 3, Shutter Speed)

May 252010
 
 May 25, 2010  Posted by Habenero at 9:36 pm How To, Photography , , , , , ,  No Responses »

Shutter Speed is the length of time the sensor or film is being exposed to the light. Early films often used shutter speeds measured in minutes, which made portraiture a painful experience. Modern cameras allow for much shorter exposures, rarely more than 1/8th of a second. When choosing your shutter speed, the important things to remember are your ISO setting, the focal length of your lens, the subject matter, and your own artistic license. If you like to shoot and freeze a moment in time, you are more likely to use a fast shutter speed, as are those who prefer to hand hold their cameras.

The rule of thumb for choosing a particular shutter speed for those that like to hand hold their camera, as opposed to locking the camera to a tripod, is to remember that in order to minimize camera shake, one should choose a shutter speed that at the very least is 1 over your lens length in millimeters seconds. In other words, If I am shooting with a 300 millimeter lens, my minimum shutter speed should be at least 1/300th of a second. A slower speed often would result in a bit of motion blur from the movement of the lens relative to the subject. That is why you often see sports and wild life photographers mounting their lens on a heavy tripod.

Image Stabilization, Vibration Reduction, or what ever name your camera or lens manufacturer wishes to call their lens system that enables you to shoot hand held at longer than the recommended shutter speeds, would permit the average person in the above example to effectively shoot using half to a quarter of the speed or 1/150th to 1/75th of a second. The thing to remember is that just because the system has reduced the motion induced by your own movements, it can not in any way compensate for the motion of the subject.

Shutter speeds are not always chosen to freeze time. In order to convey a sense of motion, it is often desirable to use a slower shutter speed and pan with the subject. You can also use rear curtain sync with your flash to allow some motion of the subject to be captured. One can also use multiple flashes or strobe lights with slow shutter speeds to add a real sense of motion to their images. Be creative and try things that make your pictures portray your sense of the world. Don’t just record an instant of time.

Camera Controls (Part 2, F-Stop)

May 182010
 
 May 18, 2010  Posted by Habenero at 10:10 pm How To, Photography , , , , ,  No Responses »

Aperture or F-stop is the lens opening that controls how much light will pass through the lens. Regardless of the size of your lens, sensor, or film plane, a given f-stop will allow the same amount of light per square centimeter (or inch) to go past. The number selected for an f-stop is actually the denominator of the fraction 1/f-stop. The higher the f-stop number, the smaller the opening and the less light that will be admitted for your exposure. The f-stop controls your depth of field. A low number ensures that from near to far focus points a shallower area of clarity will exist. At higher numbers, the area that is in focus increases.  Part of what makes an image interesting is having your eyes drawn to certain areas within the image.  It is not important to have everything in the image tack sharp.

The danger in using small apertures is that they also increase diffraction of the light through the lens. On film, diffraction is not as much a problem as it is on a digital sensor because color spilling over onto another grain doesn’t cause the entire grain to react (individual atoms within the grain do react, but not the entire grain), but pixels react under a different set of rules and any light that spills onto even part of a pixel will trigger the entire pixel to react which softens the overall sharpness of the image. That is one of the drawbacks to using a digital camera in a situation that calls for keeping as much area in focus as possible. When in doubt, take the picture anyway and as your skills in processing your images increase, you may find a work around to the problem.

Selective focus is the principle technique that separates good photographers from the larger set of people that take pictures. Selective focus requires using your depth of field to keep the area of interest clear while letting the rest of the image blur. Sometimes, the blur will take on an appealing characteristic called bokeh. Bokeh is caused by the shape of the iris in the lens and the light pattern of the scene being photographed.  Not all lenses create good bokeh, which is one more reason testing a lens on your camera prior to buying it is important.

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