Camera Optics: Digital vs SLR (Optical Zoom)

[BScott881]

Digital zoom is measured in (x) enlargement and SLR in millimeters. Example: a digital camara might be 3x or 4x or in my case 10x zoom while a comparable SLR lens might be 80mm or 300mm. How do you make comparisons between the two?

 

[Mem]

Ignore digital zoom since that will reduce the image qaulity on digital cameras,look for optical zoom,most optical zoom cameras are around 3x optical zoom this is normally equal to a 35-105mm lense (on a normal film type 35mm camera).

The quality of enlargements depends on quality of the lense and the actual setting used(ie 800x600,1600x1200 or higher etc) which depends on the MP rating of the camera, which can be 2MP,3MP,4MP,5MP etc,the higher the better for very big enlargements.Remember a 5MP(megaPixels) camera will have a higher resolution then a 3MP camera which would be handy for very big enlargements.

Getting back to optical zoom,I know on the Olympus C-730 and the newer C-740/750 models which are coming out real soon all have 10x optical zoom lenses which is equal to a 38-380mm zoom lense on a (35mm film camera).

For info on digital camera reviews and FAQs go here .

and to here.

Remember

Optical Zoom - Means that the camera has a real multi-focal length lens, this is not the same as a "Digital Zoom" which magnifies the center portion of the picture.

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[warmonger]

They aren't really comparable. Digital zoom crops and enlarges the picture. Optical zoom changes the field of view, which is basically magnifying. So, if you use 100mm optical and no digital zoom, that would not look the same (in both quality and the actual image itself) as 50mm optical and 2x digital zoom.

 

[mroptimistic]

Originally posted by: BScott881
Digital zoom is measured in (x) enlargement and SLR in millimeters. Example: a digital camara might be 3x or 4x or in my case 10x zoom while a comparable SLR lens might be 80mm or 300mm. How do you make comparisons between the two?

They make comparisons by taking the highest focal length and dividing it by the lowest. Example a slr zoom lens that ranged from 80-300 would be 3.75x zoom. They usually round the number for example the minolta dimage 7 series has a 7.14x but they just say 7x. It changes per camera, you can't just say a 3x zoom is 35-105, thats assuming the lowest is 35, there are variences. The dimage 7 series goes from 28-200, instead of 35-250.

Now with digital zoom, you shouldn't even take that into consideration. Some cameras resample, but many its just a crop. Either way the same thing can be done much better in photoshop. Digital zoom is just cropping out portions of what the lens sees and then magnifying it. You loose detail and for those cameras that dont resample it is the same as just cropping in photoshop and then increasing image size. The ones that do resample, well you can resample in photoshop with better results. Basically digital zoom is a convenience thing if your just point and shooting and dont worry too much about perfect clarity and detail and you dont want to post-process.