I'm photography enthusiast, But I'm unaware of the difference between my camera's macro mode vs zooming in with a telephoto zoom lens
What difference does it make when I zoom in with a telephoto lens onto a small flower, vs just switching into Macro mode in the camera to take the picture of that small flower?
Could someone please clarify?
Macro mode on compacts usually zooms to the longest setting, and DSLR lenses with a macro setting will only allow to engage it when fully zoomed. Edit: this may not be true for all models as mentioned in the comments.
When you turn on macro mode, the lens is able to focus closer than normally possible, and the AF system may be tweaked to prefer close objects.
So, if you are able to make the shot you want without engaging macro mode, that's perfectly fine, but you may need it so you can get closer to your subject and still get it in focus.
A macro or flower scene mode, as opposed to a macro switch on a DSLR lens, may of course tweak other settings, too, like aperture and colours.
The difference is the minimum focusing distance each lens can use. This affects the lens' Reproduction Ratio which is also sometimes called the Maximum Magnification (MM) specification. Most lenses that are considered true macro lenses have a Reproduction Ratio of 1:1 (the MM is referred to as 1.00X). There are a few macro lenses with a 1:2 ratio (0.50X MM). What this means is that a macro lens with a 1:1 reproduction ratio can project a virtual image on the film/sensor that is the same size as the subject of the picture. If you are using a 36X24mm full frame sensor and a lens capable of a 1:1 reproduction ratio, the image of a 24.26mm wide U.S. quarter would be ever so slightly too large to fit across the narrow side of the sensor!
Most telephoto lenses, especially the ones with focal lengths beyond 200mm or so rarely have an MM greater than 0.20-0.25X. They can make distant objects look much closer, but they typically can't focus close enough to small objects to create a life size image measured as it is projected on the sensor. Most macro lenses can focus on objects much closer to the camera. In some cases they can focus as close as the front of the lens! This helps to magnify very small objects in a way that shooting them from several feet away can't.
