You should never try to clean your sensor with physical contact. It's very likely you damaged the imaging sensor when you used your cleaning chemicals. Now you might be faced with an expensive repair because the sensor probably needs to be replaced. The sensors have a protective but very thin veneer coating of lacquer that is easily damaged. Physically contact can do irreparable damage to the coating and the only way to repair it is to have the sensor replaced. A "puff duster" or compressed air is all you should ever use and even then, only sparingly. The "CMOS" and CCD Sensors are extremely sensitive and can be so easy to damage. I always take mine to a professional when I need or want it cleaned. That way if it gets damaged, the repair shop is responsible for repairing any damage, or replacing my camera if it becomes necessary in the event the camera is damaged beyond repair.

If you see dirt on your sensor that won't blow away, it should be taken to a reputable and certified camera repair shop so they can do it for you. The technicians have the equipment and training to do this.

Since you may have damaged your sensor beyond repair, your only other option is to buy a new camera and send the one you have out for repairs. Be sure to ask for a quote on how much it will cost to fix and be absolutely sure that they put the estimates in writing.

Rarely do anyone except photographers ; and even then not all, view the work up close.

When reviewing a darkroom print I always want my students to stand at the viewing distance for print size. They tend to put their nose up as close as possible.

A fellow I know who is a commercial shooter once told me, "in over 40 years, he never had a client view an image that close or complain about the grain (noise).

There is a much different look of a photo taken with 35mm film and one with 8 x 10, but even then without any experience a novice might not even know.

Bruce,

Wrong assumation. full frame = 35mm film but in reality are a bit smaller; however, the difference is very small. crop sensor = a significantly smaller than a 35mm negative, that is why the crop factor is applied to the focal length to indicate the viewing section of the sensor.

The pixels are larger on the full frame and so more information can be recorded.

RAW contains more information but when the micro chip takes this information and compresses it to a jpeg file it can't use it all and discards it , never to be seen again (at least as a jpeg file). If you shoot both then you can go back to the RAW file which has retained all that info.

With film, as the film size increase the amount of information capture increases and the level of detail and tonal range increases which in turn give the image a significant difference.

There has been a continuing discussion to compare digital to film trying to determine at one point will the DLSR match
or better MF film.

If you have ever seen an image from a digital back placed on a MF or LF camera you will discover there is still a long way to go.

To the trained eye, there is a difference between a ff sensor and a cropped one. Subtle but a difference.

Personally I wish they would stop cramming so many pixels on such a small surface, at some point something has to give as has been suggested in another response. Would rather see more research go into the noise control factors and the quality of the sensor it's self.

I am surprised that Sony treated you that poorly. As for their extra warranty is concerned, I asked them if it fell in the toilet, would they repair or replace it. They said yes. I even have it in writing.

All alpha and Minolta af lenses are interchangeable. The a77 is a great camera but you will have to get different lenses in order to get the most out of that camera. Besides, the a77 is about $2000.00 with a basic lens. The a55 is a great little camera and you can't beat the price for all the features that it contains. If you are worried about weather damage, Sony offers a 4 year anything goes warranty for $169.00. This comes in handy. My wife's oldest son is a jerk just to be polite. For reasons only known to him, he put my whole camera (a500) bag in the microwave. Not only did Sony fix it, they also replaced the 3 Sony lenses that got fried also at no charge. Their service was fantastic!

I then purchased the a580 which I totally love. I thought about the a55 but I opted for a traditional DSLR instead which the a580 is. Both have the same great sensor. The a 55 has auto focus in movie mode while the a580 does not. Since I could care less about shooting movies from a camera, this point does not bother me.

In other words, go ahead and purchase the a55. Your lenses will work just fine and you will be happy.

Do you mean the Nikon D700, which is full frame? The D7000 is the same size as your D80. The Sigma 105 is 152 mm equivalent on the D80 and D7000, so it would be 105 mm on the full frame D700, and you would need to get closer to the subject to get the same composition, a problem with subjects that might be spooked, like insects.