Studio Workshop Wanderings

Green Valley Photographic Information -- A new cover for Al Crawford's Website of Photography Resources.  This will include links to Al's handouts as well as other information that is included in this newsletter.  You may get there directly by clicking on the link that begins this paragraph or by clicking on the Photography Resources link on the Green Valley Camera Club front page.

Workshops for this week

All workshops are in the Camera Club Studio Classroom and do not require a sign-up.

Intermediate Digital Photography Workshop

Thursday, March 15, 9:30  to 11:00
"Photoshop Elements Organizer" presented by Howard Benedict

Everybody has thousands of photographs that they have taken over a lifetime stored in their computers from a digital camera or in boxes of Kodachrome slides or strips of negatives. Finding a particular photograph out of thousands is a daunting task. This program offers an easy to use system for photo file management that has earned all the top magazine awards as the best photography file management program. Once you have organized your photos there are several additional creative projects you can learn to do i.e. Slideshows, Creating and printing greeting cards, email cards and printing photo calendars from your photos. It is an easy to understand system that can locate any digital photo up to a 50,000 limit in less than 10 seconds. It uses the same sophisticated data base management system that has made Quicken so popular because of its comprehensiveness and ease of use.

Time will be given at the end of the session for questions and answers.

Advanced Digital Photography Workshop

Thursday, March 15, 1:30 to 3:00

Note:  There will be no Advanced Workshop on March 15th.  The Advanced Workshops will resume on March 22nd.

The topic for March 22nd will be Adobe Lightroom.  This is a new Adobe product that would work well for advanced users of both Photoshop CS2 and Elements.  It includes a Library module which helps organize your images and a Develop module which is based on the Adobe Camera Raw 4.0.  The develop module will work non-destructively with JPEG files as well as with Raw files.

Black & White Study Group

Friday, March 16, 9:30 to 11:00
"Giving Your Images Depth" a discussion lead by Nancy Spear

Nancy Spear, who has a background as a painter (not the house kind but rather the artist kind), will discuss the problem of putting 3 dimensional objects ( what we photograph) on a 2 dimensional plane  ( paper) .  Since we don't have color to help, we'll look at the  importance of other aids to make the photos we take look 3 dimensional.

As you photograph this week, think about dimension.   Bring your  successes and past failures to class for us all to talk about.


Featured Website of the Week

Each week or so a website will be featured here. 
        This week is featuring the website of  the Digital Imaging Group, a photography club located in Scottsdale, Arizona.  DIG meets once a month and has a very rich program each month.  DIG sponsored this past month a sold out seminar presented by George Lepp, who is a nationally known photographer and photography teacher.  The DIG website is a part of the website EZPixels which is the website of Marianne Wallace whose energy is a major reason DIG is such a fine photography club.

How Many Pixels Do You Need

A discussion occurred a few weeks ago among some GV camera club members about how many megapixels we need in a digital camera.  The megapixel war between camera makers almost seems to be unending.  Right now if you buy a new digital camera about the smallest number of megapixels would be about six and many point-and-shoot pocket cameras have up to 10 megapixels.  And you could spring for a Canon 1Ds for about $7000, without lens, and get 16.7 megapixels.  And if you wanted the ultimate and have a very large amount of money you could spend $25,000 for a Hasselblad which would get up to 39 megapixels.

Now what would all of this get you?  The answer is that it depends greatly on the camera.  Pixels are not the same from camera to camera.  A pixel within a digital camera is represented by an electronic light sensor covered by a microlens and a red, green, or blue filter.  The larger a pixel sensor is the better it can collect light.  The closer together the pixel sensors are the more they interfere with each other.  So the larger the camera sensor (the collection of all the pixel sensors) the better quality of image you are likely to achieve.

The Hasselblad sensor is 49.0 x 36.7 mm in size.  This holds an array 5412x7212 pixels (39 megapixels) for a pixel density of about 28,000 pixels per square mm (p/smm).  If you look at the Canon 1Ds  you will find a sensor that is 36 x 24 mm in size (the size of a 35 mm frame) and it will produce an image of 4992x3328 pixels.  This will give you a pixel density of  about 19,200 p/smm.  This is part of the reason why the Canon will give almost as good of results as the medium format camera and why the Canon has an ISO rating of up to 3200 where the Hasselblad max's out at 400 ISO.

The most common DSLR cameras have a sensor size of about 23 x 15 mm.  If you put 10 megapixels in that area you would get a pixel density of close to 30,000 p/smm and a point and shoot might have a sensor size less than 16x12 mm so a 10 megapixel point and shoot could have a pixel density of greater than 50,000 p/smm.  So the quality of those cameras will not be as great as the ones with larger sensors.  But camera makers are improving their sensors constantly and they are finding ways of packing more pixels in the same size sensor while keeping the quality up.  So maybe more is still better.

Now what does all of this mean.  If you are going to print only images of 5x7 inches or less and you do not crop your images then it means absolutely nothing.  This is because a three megapixel camera will give you perfect photo-quality prints of up to 5x7 under anybody's guidelines.  And actually, you can get very satisfactory 11x14 from that same image and if the original image is very sharp you could even go up to 16x20.

Why is this?  The most conservative of photographers will say that you need 300 pixels per inch to produce a photo-quality print.  And this would give you about a 5x7 print from your 3 megapixel image.  But to get up to a 16x20 using those guidelines you would have to have 31 megapixels.  Be ready to spend $25,000.  But in practice you have much better latitude than that in making your prints.  I just got back from a seminar in Phoenix that displayed a photo of a giraffe that was 50 inches wide and 144 inches high (taken with a Canon 1Ds using multiple shots and Panarama Maker).  And even when you viewed it at one foot it looked very sharp.  Photoshop's default pixels per inch in their raw converter is 240.  And you can go down from this.

If in Photoshop (CS2 or Elements) you resize your image by unchecking "resample image" and setting the resolution to anything greater than 180 then you still will get a photo-quality print.  (Try it if you don't believe me.)  Furthermore, by checking "resample image" and doubling your image size you could get up to a 16x20 out of your three megapixel file and up to 25x34 out of a seven megapixel file.  Of course, to get a print that big your original will have to be sharp.  And to get a picture that large you will have to send it off to be printed.  For more on this see my handout by clicking here.

So the main advantage of a large megapixel camera seems to be the ability to crop.  And, as photography has always been, the film (or the sensor) is only one part of the reason an image comes out sharp.  Maybe the most important part is the lens.  So without a sharp lens you will not get sharp images.  And it is the quality of lens that  you are normally paying for when you spend extra money on a camera

Al Crawford.