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Picture quality for the beginner & a little advanced

Started by Hawks Feather, October 18, 2009, 01:40:29 PM

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Hawks Feather


Hopefully this will make sense to those of you taking photographs of “items” that are small.  If you have questions feel free to send me an email.  And before anyone asks, this is NOT directed at anyone in particular, just trying to help.

Jerry

Beginner:
As you all know, from time to time pictures of calls and other close up pictures show up and are not sharp (my term for not in focus).  I have shared what can be done about this with a few people and thought it might help to have a picture or two to show what is really happening.  Now with that being said, I am using a digital SLR and have the advantage of being able to adjust just about anything related to taking a photograph â€" f-stop which allows you to choose how much will be in focus, shutter speed which allows you to stop action and doesn’t relate all that much to taking pictures of small things since most are sitting still, and being able to override what the camera “thinks” is a balanced exposure.  Most of the point and shoot digital camera or cell phone cameras don’t offer these options, but you can fool your camera.  The best way to do this is to not use the flash, use a tripod, and use a neutral density gray card.  On almost every point and shoot camera there is an option to turn off the flash â€" that is pretty easy.  A tripod is a great big expensive thing that I can’t afford.  That could be partly correct but for the most part is wrong.  There are small “table top” tripods that you can find at Walmart, Meijers, and other discount places and also on the internet (but you will usually end up paying shipping there which might make the one at the local store a little more reasonable in price).  A neutral density gray card can be found at many camera stores and some of the larger discount store’s photography section.  I have a WhiBal, which is overkill for the average person.  If all else fails try to get a piece of light to medium gray construction paper.  Now with that being said, unless you use a white or black background you might not need it at all.

So now that you have these items what do you do?  Just set up the call or other small “item” and take the picture right?  Nope, now the work begins, but it is pretty easy.  Most point and shoot camera auto focus and they focus on the BACKGROUND, not the small object that you want in focus.  If you look at the following focus chart you will see that (despite what we think) not everything in a picture is always in focus.


When you look at this picture you can see that the very center is in focus and that just a short distance behind and in front of the “focus line” things start to go out of focus.  This is what is happening with a point and shoot camera â€" it is focusing just behind or in front of the small “item” and not on the “item” itself.  There are two ways to take care of this â€" one is to give the camera more area to focus on around the small “item” (like holding it in your hand) and the second requires a little more time.  To do the second option it really helps if you have the tripod or an additional pair of hands.  To do this you set the small “item” up where you want to photograph it, put the camera (preferably on a tripod) a short distance from the “item”, place the neutral density card or something for the camera to focus on at the spot of the “item”, press the shutter release about half-way down so that the camera sets the focus, KEEP the shutter pressed half-way down while you remove the larger item where the small “item” is sitting, and press the shutter release the rest of the way down taking the picture. 


WhiBal card used to focus and set exposure



Remove the focusing card and shoot



Without the focusing on something at the point of the call, this is what you might get.  Notice how it is not as sharp as the picture above.  It focused on something that I really didn’t want.

If you want to take another picture of the same “item” you need to again repeat the procedure of inserting something for your camera to focus on at the spot of the “item”, press the shutter release half-way down, remove the item, and press the shutter release the rest of the way.


A little advanced:
Shutter speed and f-stops are related and the easiest way to think of them is to put one on each end of a balance (teeter totter for those of use who have spent too many years on a playground).  The camera looks for a balance of shutter speed and f-stops so that the balance is level.  If you change one end of the balance either the camera or you have to change the other to make it continue to be level.  This is where having a digital SLR comes in really nice.

So, what is an f-stop and shutter speed and how do they relate?  Good question and the best way to think of this is how to fill a cup with water.  There are many ways to fill a cup with water â€" one drip at a time (over a long period of time) or at the other extreme, from a 4-inch fire hose where it will instantly be filled.  In the middle is the kitchen sink where you get more than a drop at a time but less than the fire hose.  The kitchen sink is where you can usually get your best pictures.  So how does this relate to a picture?  Well the rate of the water is the f-stop and the amount of water is the shutter speed.  As one increases the other decreases.  The following picture show what happens at f 2.8 with an exposure of 1/200 of a second.



The low f-stop of 2.8 does not allow much to be in focus on the focus chart.



This is the same focus chart when the f-stop has been moved to f-32 and not at f-2.8 like the first picture.

There is much more in focus but the exposure time had to be increased to .4 of a second.  That is the balance that I mentioned earlier â€" when more is in focus (higher f-stop) the shutter needs to be open longer to allow the balance to happen.  Without a tripod there is no way that I would be able to get a picture that wasn’t showing movement a .4 of a second.  By being able to adjust your f-stop to a higher number you will get more in focus.


I have long been a fan of using a neutral density gray card for exposures and now it can become even better â€" especially if you have a program that will allow you to match the neutral density card reading and copy those into another image.  Photoshop used to work really well for this, but alas my copy of Photoshop is outdated for my current computer and I am too cheap to pay for the upgrade.  While these may not show a true comparison, the picture on the top was taken with the averaging exposure set by the camera and the second was taken with a reading from the neutral density card.  The white is much truer when the neutral density card is used.



Average exposure by the camera


Exposure from using the neutral density card.


WhiteHare

So, what you are saying is to put your small items in the sink and then take the picture? 
   
QuoteThe kitchen sink is where you can usually get your best pictures. 

Just kidding Jer.......see what happens when I take things out of context.  I get pretty good at that sometimes.

A very good tutorial for anyone taking close up pictures of calls, flowers, or any other smallish items.
You have put it into terms that most should be able to understand.   Not pointing fingers here either.

I might add that to keep all of the item in focus you should keep it parallel to the rear of the camera.   Putting things at an angle from front to back may allow just the middle or a part of the item to be in sharp focus.   This would be another lesson for someone to provide.

Richard
WhiteHare Lanyards
Richard Hughes

www.white-hare.com
whitehare@white-hare.com

Hawks Feather

Quote from: WhiteHare on October 18, 2009, 09:22:35 PM
So, what you are saying is to put your small items in the sink and then take the picture? 
   
QuoteThe kitchen sink is where you can usually get your best pictures. 

Just kidding Jer.......see what happens when I take things out of context.  I get pretty good at that sometimes.

Richard

Yep, you need to move to the tub for your medium sized "items" and a swimming pool for larger "items."    :innocentwhistle:

Wolfwoman

Or you could just get a really good camera with a macro feature. This flower is about 1/2 the size of a pencil eraser.
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timbertoes

The key is enough light. :)

enough light = no tripod needed.
enough light = Fstop higher, more front to back focus.

Keep a lookout for good deals on a oh, about 400 watt second strobe.  (craigslist or local used camera store)
Then you can shoot handheld, even at higher fstops, with a shutter speed in the 125 or 250 range.

Or also a standard camera flash unit, and a $50 to $80 softbox made for them :)   www.strobist.com

somewhat too many choices, but if your camera does not have a hot shoe or flash synch port...  above wont work.
However, there are a lot of older, used perfectly good 6 and 8mpixel Nikon and Canons out there for pretty cheap.
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