NorthIdahoLeather

Light box? Please help!

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On 11/7/2019 at 10:05 AM, Northmount said:

I'll try to put this together in simple terms hopefully to make it easier to understand more complicated concepts later.

ISO is how fast the film is, or rather a measure of how much light it needs to be properly exposed.  In place of film, you now have an electronic image sensor.  High ISO numbers mean fast film (or equivalent) and tend to produce grainy photos.  Lower ISO speeds produce finer detail, less grain.  Since a low ISO number needs more light, you have to supply more light by either opening up the lens aperture, or by keeping the shutter open longer.

Lens opening (aperture) is measured as f-stop numbers.  The lower the number, the wider the opening and the greater amount of light is let through the lens.  f5.6, f8, f11, f16, f22 are examples.  As you go from a higher number to the next lowest number on your lens, the amount of light delivered is doubled. 

Depth of field is an interesting item.  It describes how much of the object being photographed is in focus measured from front to back.  A pinhole camera has great depth of field.  So that tells you that a small aperture increases the depth of field.  If you want the background to be mushy, out of focus so it doesn't detract from your prime object, you work with a large aperture (low f-stop) to provide a shallow depth of field.

Exposure time ... if you double the exposure time, say 1/125 second to 1/60 second, you double the amount of light the sensor receives during the exposure. 

If you want great depth of field, you move to higher f-stop numbers. For each number you increase your f-stop, you will need to double the exposure time.  So if you had set your camera for for f8 and shutter speed of 1/125 second, and want to increase the depth of field, you could go to the next highest f-stop number, f11 and increase the exposure to 1/60 second for the same effective exposure.

So looking at f-stop, each increment halves or doubles the amount of light received by the sensor.  Looking at shutter speeds, the marked shutter speeds on most cameras also halve or double the amount of light received by the sensor.

Fast shutter speeds help eliminate the effects of camera shake.  Slow shutter speeds require a very steady camera so most often require a tripod.  Most people can get reasonably crisp photos at 1/60 second or faster.  Wide angle lens can extend the apparent steadiness; longer lenses, telephoto magnify camera shake so need a solid support for crisp photos.  Macro shots need a steady hand or tripod.

There's lesson 1 and 2.  Now get your camera and experiment.  At least with a digital camera, there is no film cost hindering taking lots of practice shots.  Just be discriminating and delete all but the very best, else you will use up lots of storage space!  When practicing years ago, I used to shot 2 or more 36 exposure rolls of film per week.  So a lot of those were B&W to reduce film and processing costs.

One last comment, under-exposing a shot by 1/2 to 1 stop can increase the colour saturation.  Sometimes useful to do.  And of course the opposite, too much exposure washes out colour and detail.

Tom

Tom,  thank you for taking the time to spell that out for me. I’ve been reading as much as I can, but you have answered some of the questions that arose from my studying. New camera will be here tomorrow. I’m hoping to have a chance to get some practice time using your comment as a reference. Great info and I really appreciate it. Thank you! 
 

For those who were kind enough to steer me away from a light box/ tent,  yoj were right. It’s a total joke. Spent a couple days with my iPhone trying to get a decent picture.  Shadows?  I couldn’t get rid of em  and those that said the sheets they supply were bad? Horrible. No matter what I do, I can’t get rid of the wrinkles. But, now I know. Lol 

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