Diffraction affects your image sharpness by limiting Depth of Field and useful Resolution. See how our camera and lens choices influence these limits.

To increase Depth of Field we simply decrease aperture (larger f-stop). However, we cannot get infinite Depth of Field by decreasing our aperture infinitely. Diffraction establishes the upper limit to Depth of Field.

The subject may seem very technical, but the solution is far from being difficult. To understand this tutorial better, consider reading my Correct Exposure Series of Tutorials and my previous tutorial on Hyperfocal Distance, which explains the relationship of aperture and Depth of Field.

Diffraction is an optical effect limits the resolution / sharpness of our photograph. Since it is an optical effect, higher resolution sensors will not improve resolution further. Higher resolution cameras are thus more demanding on our optics and eventually will yield little to no improvement in total resolution. Diffraction plagues landscape photographers who are striving for a large depth of field and high-resolution images. Many of us are not even aware of this, blindly selecting a small aperture according to our calculators and charts.

The Culprit: Broken 80GB Wester Digital DriveThree to four weeks ago, I got the shock of my life. I turned on my main Photoshop Computer that also holds all of my photographs in form of undeveloped RAW files. Suddenly my computer reported that it could not find any hard drive to boot from and it made loud clicking noises. One of my drives was trying to spin up but could not. It sounded very much like a head crash.

The next day was pure agony for me, when I had to wait to dissect my computer. Although used to back up everything to external drives, I had become lazy recently. My most recent backup was already several months old. I took my internal hard drive to usb adapter and hooked up my main picture drive to my computer. The adapter works with Laptop and Desktop drives as well as the new SATA drives.

Edge Tech Corp. Digital Picture Frame
Size Comparison Ever since I have built my own DIY digital picture frame a while ago, I have kept an eye on the market for commercial frames. I have not bought any, due to the high price of large high-resolution digital picture frames (DPF). During this Christmas shopping season prices have dropped considerably, causing a run on these devices at my local Best Buy store. Therefore, I was looking forward to a new gadget when EDGE Tech Corp asked me to review one of their devices.

Well, I guess thats a bit too strong of a statement. I have bought many things on Ebay and I am very happy with most of my purchases (e.g. the backup server does great and was a steal). However I will not ever buy a replacement battery on Ebay again.

Background Story:

A while ago I bought to replacement batteries for my and Dani's IPAQ PDA. Those batteries are very high capacity Li-Polymer Batteries that look something like that when bought new:

After I installed the battery, the device worked for a relatively short period of time until it started to act funny. It forgot the CF expansion card and shortly thereafter, the screen started to develop black spots. I still wasn't aware of the problem and I thought that the LCD would have reached its end of life. Funny thing that Dani's IPAQ would start to fail around the same time.

Finally yesterday I realized that the IPAQ hat pushed its extension sleeve apart and the device was bulging like a balloon. The reason I hadn't noticed any of this earlier was due to the fact that it was sitting in its extension sleeve. After I took the device out (see first picture on this page) I realized that it was bulging.

I opened the device and the back panel almost sprung into my face. It was under a lot of pressure and completely deformed:

The battery which should be flat (see picture of new battery) was blown up like a balloon.

When you get it new, it is probably as thick as 2 or 3 credit cards put together. The one I removed from my (now deceased?) IPAQ looked horrible.

The bottom line: I should have known better then to buy a replacement battery on ebay. Let this be a warning to you in case you are thinking about it.

I won't buy any camera equipment on Ebay either after a horrible experience with a lens.

This guest article was contributed by Brian White from Background Exposure.

Warning: Reading this article may diminish your enjoyment of some photographs you view in the future because you will start to observe a flaw that would previously have gone unnoticed.

A camera lens has many different attributes. There is focal length, zoom, minimum/maximum aperture, sharpness, and chromatic abberation... and that's just off the top of my head. Lens manufacturers only tell the basics like focal lengths and apertures. Third party reviews will often get in to sharpness and "fringing". But most of these reviews are concentrate on subjects that are in focus. They usually ignore those parts of the photograph that are outside the range of "acceptable sharpness" since they're assumed to be unimportant. After, all, if they important, they would be in focus. Besides, it's all blurry anyway, right? Not always.

Have you ever edited a digital picture on your home computer, possibly with a discount LCD display, sent it off for printing just to realize all the colors were somehow differnt then they were on your screen? While most people may blame the results on the photo processing lab, here is a surprise for you. It may actually be your wrong doing that made the image look all wrong.

I have found that most commercially available LCD screens have a greenish or blueish cast and pictures usually look somewhat "cooler" than they should. Most of us are not used to the idea that what we see may not be a good representation of our picture. We tend to trust our LCD screens. Some of us may have spent a lot of money on expensive equipment and we have bought a software like photoshop to "get the most out of our pictures". Adjusting a picture with such a screen "to look better" may actually lead to a deterioration of image quality as we unknowingly make things worse. Welcome to the wonderful world of color calibration and color profiles.

In this tutorial I will walk you through the steps to create your own digital picture frame from a junk laptop. This is a great way to recycle your old laptop that has been laying around for a while and create something new and useful. I will touch all aspects from the hardware modifications required, to the software and the preparation of your pictures. I will then show how the final product looks like (it can play video too).