Camera differences

[Kieran Aldridge]

Hi all, I am getting into photography and would like a few tips and pointers if you will aid me in getting them please?

I currently have only a digital camera with 10x zoom and a focal length of 18-55.

I am going to invest in a SLR camera soon, however, the ones that I have seen have a focal length of 18-55 also. Could someone please tell me what the difference is between a focal length of 18-55 on a digital camera and a SLR camera? And the benefits of a SLR camera over a normal bridge camera with 50x zoom?

Thanks

Kieran

 

[chris-red]

Get ready for some maths,

zoom is a factor of focal length divided by sensor(film size)

so on a 35mm film camera a 350mm lens would be a x10 zoom.

Most non pro Digital SLR's have an slightly smaller sensor than 35mm film about 22mm or so, a 18-55mm lens on one of these cameras is about a 0.7-2.5 zoom.

You compact will have a much smaller sensor than an DLSR that is why it has a longer zoom.

Generally the bigger the sensor the better the image quality. It is the same with bridge cameras they have smaller sensore so can have longer zooms from the same focal length. However the image quality will be worse.

 

[hollis_f]

Get ready for some maths,

zoom is a factor of focal length divided by sensor(film size)

so on a 35mm film camera a 350mm lens would be a x10 zoom.

Zoom is measured as longest focal length divided by shortest focal length. It has SFA to do with sensor size. So an 18-55mm lens is a 3x zoom. A 100-400mm lens is a 4x zoom.

 

[chris-red]

Zoom is measured as longest focal length divided by shortest focal length. It has SFA to do with sensor size. So an 18-55mm lens is a 3x zoom. A 100-400mm lens is a 4x zoom.

Then where the fudge did I get that from? That was how I was taught it but it appears to be complete b*****ks!

 

[viewfromthenorth]

Hi all, I am getting into photography and would like a few tips and pointers if you will aid me in getting them please?

I currently have only a digital camera with 10x zoom and a focal length of 18-55.

I am going to invest in a SLR camera soon, however, the ones that I have seen have a focal length of 18-55 also. Could someone please tell me what the difference is between a focal length of 18-55 on a digital camera and a SLR camera? And the benefits of a SLR camera over a normal bridge camera with 50x zoom?

Thanks

Kieran

I'm not sure how your camera has a focal length of 18-55 AND a zoom of 10x. As Frank says, 18-55 is 3x zoom. Also, compacts and bridge cameras don't tend to go that wide and they tend to quote the equivalent focal length of a 35mm / full frame, e.g. my Fuji X10 has a 7.1-28.4mm lens which is a 4x zoom and 'equivalent to 28-112mm on a 35mm camera' according to Fuji's website. SLR lenses don't tend to be marketed or labelled with their zoom factor, e.g. they're just sold as a 24-105 or a 70-200.

The world of focal lengths can get confusing quick, and usually ends up in arguments around fields of view and sensor sizes. You'll find all you could possibly want to read on that subject in the talk basics forum!!

In terms of advantages, of an SLR - better optical quality from the lenses, less noise from the sensor (meaning cleaner images in lower light), better dynamic range, normally better image quality if you are printing big, and doubtless others I've forgotten. Advantages of a bridge are no lenses to change or buy, lens versatility in terms of focal length, smaller and lighter in size.

 

[Phil V]

Andy has it covered. He just missed the shutter delay and focus speed which are generally loads better on an SLR.

However, a decent bridge camera is capable of great results in the right hands in the right conditions. And there's CSC's to consider nowadays, for people who want (most of) the advantages of an SLR in a smaller body.