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Re: Question about SLR and zoom lenses

the Omrud <usenet.om...@gexpungemail.com>

Mentalguy2k8 wrote:

> "the Omrud" <usenet.om...@gEXPUNGEmail.com> wrote in message
> news:s974m.52038$OO7.34571@text.news.virginmedia.com...
>> Mentalguy2k8 wrote:
>>> Hi,

>>> I'm looking to buy a mid-range SLR digital camera, are there any
>>> pitfalls I should be aware of?

>> Many, I'm afraid.  It's not easy to know where to start.

>>> Also, I'm looking at zoom lenses to go with it, how do I work out
>>> what magnification they are, eg 5x, 10x etc? For instance, this lens:
>>> http://shop.panasonic.co.uk/invt/hfs045200e

>>> says "90 to 400 mm (35 mm equivalent)" and "Maximum magnification:
>>> Approx. 0.19x / 0.38x (35mm film camera equivalent)".

>> SLR users don't tend to talk about 5x, etc, especially those of us who
>> have been taking photos since the 1950s.  What's interesting are the
>> two numbers of the zoom, e.g. 35 to 135, 90 to 400, etc.

>> 50/55mm  is 1:1 real-life size.  So your lens above is a zoom, from
>> medium long to very long, a little more than 4x zoom range.  To
>> confuse matters, many mid-range digital SLR cameras have sensors
>> smaller than an original 35mm film frame, so the magnification of any
>> lens is different from when you use it on a "full frame sensor"
>> camera.  If you need to know why, you should read up on focal length,
>> e.g.:
>> http://en.wikipedia.org/wiki/Focal_length.

>> Why did you choose this lens?  Would you never want to use a
>> wide-angle lens, as if you only have one like this, you wouldn't be
>> able to.

> It was really just an example, as one of the cameras I was looking at
> came as a package with this lens as a 2nd lens here:

> http://www.pixmania.co.uk/uk/uk/2895441/art/panasonic/lumix-dmc-g1-in...

> the standard lens also supplied is 14-45mm

That's surprising for a "standard" lens - 14mm is very wide angle and
the whole zoom range is wide angle, compared with the standard 50mm,
although it would be different on a small sensor SLR.

>>> Can anyone tell me what this equates to? I'd preferably prefer to buy
>>> a camera package with a separate zoom lens, any recommendations for
>>> decent UK-based sites or shops? I'm currently looking at the Pixmania
>>> site.

>> Pixmania will deliver at a good price, but I have heard that they are
>> not as friendly as some if anything happens to go wrong.  I tend to
>> use Amazon if they have what I want.  Here's your lens:

> Thanks for the advice, I'm just browsing at the moment, I usually do a
> Google on a particular model to see if I can get it cheaper elsewhere.
> I've decided to take photography more seriously as a hobby, I already
> have a digi camera with a 10x zoom, I'd be using a new one for scenery,
> wildlife etc., so I was interested to see how the SLR zoom factors
> compared to what I already have. If I wanted, say, better than 10x zoom,
> is there a rough way to find out which lens would offer this?

Large range zoom SLR lenses are large and heavy.  Few amateurs will have
a lens with a 10x zoom range - I'm not sure I've ever held one.

Here's one:
http://www.canon.co.uk/For_Home/Product_Finder/Cameras/EF_Lenses/Zoom...
http://tinyurl.com/ouofcl

The bigger and more complex the lens, the more compromises have to be
made, so the cost goes up dramatically for a good lens as the
compromises have to be ironed out with more expensive engineering.  The
one above costs about £2000.  It would not be sensible to put it on a
cheap SLR.

But the whole point of an SLR is that you can change the lens.  So you
can buy two or three decent lenses and change them around.  I have a
cheap 55 - 80 which came with the camera (it's not very good, but it has
the benefit of being light weight), a very good 35 - 135 which I bought
15 or more years ago for my first Canon EOS film SLR, and a 100 - 300
which I bought from a friend and which isn't much cop, to be honest.

> One last question, can I use a remote shutter release with all SLR's or
> is it model-specific?

My Canon has an optional remote shutter release (infra-red, like a tiny
TV remote) which I believe will work with any Canon SLR - I think it
cost me £10.  It seems likely that other major SRL makes will have a
similar option, but any decent camera shop will tell you.

--
David