We have a 'pocket' 5.0 mega pixel digital camera which we take photos on the highest quality, biggest image setting. When viewed at full size, the images are slightly grainy. We are thinking about getting a digital SLR which will have bigger diameter lenses.
Does a bigger diameter lens mean more detail can be captured with less graining? The grainy image is not because of the diameter of the lens. It is because of the quality of the optics and also the CCD sensor that the camera is using. If you buy a newer and better model of the digital camera, you will see improvement. The SLR camera is for people would love photography and they want to have better control of the amount of the light getting to the CCD sensor and other stuffs. It is like driving a stick-shift or auto. If you are normal guy just trying to take good picture...you will go with auto...buy 8 megapixel and above of good brand will do. Else, you are the stick-shift guy...go Digital SLR. Noise (the digital equivalent of grain in film) is mostly a function of the ISO and the size of the sensor.
Larger diameter lenses (larger aperture) are used for selective focus and shooting in low light situations.
Look at the Nikon and Canon DSLR's and since they are the two most used by pros, there are many more opportunities to buy great used lenses for those cameras. The quality of your pictrues can be the lens and it can be the sensor in the camera, you don't say what kind of camera you have and the qualities do vary.
However, the most likely cause of your problem is the way the camera exposes in poor light. Some cameras will automatically boost the ISO value (that's like film speed, it makes the sensor more sensitive to light) whenever there isn't enough light to take a picture with a reasonably fast shutter speed. As the ISO number goes up you will get a grainier picture.
You can prevent this from happening by going to your set up menu and disablnig auto ISO. Then set your ISO as low as is allowed and you should have really nice pictures. However remember that by doing this you will sometimes have to use a tripod to support the camera whenever a slow shutter speed is used.
Lens diameter contributes to a picture but not as you may think. The effective maximum aperture is calculated by using lens diameter and focal length. The larger the lens diameter, the more light the lens lets through to the sensor and as a result the higher a shutter speed you can use or the more you can close down the lens to get better depth of field.
Moving to an SLR will get you better pictures but that's because the lenses are faster (they let more light through), not because they are bigger. Alas, the bigger the lens, the more expensive it is too.
If you want more detail you have two issues to address, focus and resolution. A high quality lens will get you the sharpness you expect from a fine lens but you can still end up with a less than perfect image. As your resolution goes up, say to ten megapixels, your image will become increasingly sharper too. Certainly an SLR can address these two issues but then so can a high end point and shoot camera.
I use an SLR all the time, I wouldn't think of using anything else though I do have a point and shoot too for casual images. But then I've been doing pictures for thirty seven years and I understand photographic theory so that I can take full advantage of the SLR's capabilities. If you're only going to use such a camera in automatic mode you've spent a lot of money for nothing. And if you settle for only one lens for that camera you're also spending a lot more money they you need to. SLRs are for people who demand the best quality and are prepared to utilize all the features available to achieve it. Now you can become one of those people but only if you're willing to spend a lot of time learning. If you're not willing to learn, it would be a lot cheaper and more cost effective to simply get a high end point and shoot camera.
Basically what you need is a high quality lens of any diameter, a high resolution sensor, and a sophisticated auto focus. Those are the technologies that will solve your problem. In addition to this you need to keep your ISO value as low as possible.
Finally, with a low ISO you'll sometimes have shutter speeds slower than 1/60th of a second. In those moments you need to use a tripod until you learn how to hold the camera steady. With practice you can hold a camera steady for as much as a one second exposire, I do that all the time, but that takes a lot of practice. For now you're better off with a tripod.
There is another thing too that you need to be aware of. If you crop an image and keep it the same size as the original, the result will also appear grainy because the software is creatnig additional pixels to achieve that goal. And don't forget, a computer monitor is not as sharp as our eyes. Sometimes what looks a bit grainy on the monitor is actually ok when printed. I'd use a print as the final arbiter of image quality.
I hope this helps a little. There are several possibilities here. I agree with the previous posters. The short answer is to buy a better camera, making sure it can record in a better format than just JPEG. Lenses DO matter, but in comparing a point and shoot to an SLR, it is the sensor that makes the difference. Chances are your P&S has a 1/2.5" sensor which is 20 square millimeters. Most dSLR's have sensors that are 16-18 times bigger than that. There is simply no comparison.
Here is a mini-tutorial I made myself to compare 10 MP sensors in a digital SLR (DSLR) and a point and shoot (P&S) camera. I have tried to keep everything on equal footing with no unequal cropping of the original images. Both images were taken at the equivalent of 75 mm from about 1,000 feet away. View this FULL SIZE and scroll through the image to compare the resolution at various points of the images. To me, the P&S sensor practically looks like an impressionist painting compared to the DSLR sensor. Please note also that this is the "large size" P&S sensor, as most are using the smaller 1/2.5" (5x4 mm) sensor.
http://www.flickr.com/photos/7189769@N04... |
