Got my GF1 with the 14-45 kit lens, and just wondering about what different lens offer.

The bigger the number the smaller the field of view, but what effect does the aperture have, i know a large aperture results in less of the image depth being focused. Is there any way of knowing, or is it experiment and learn (which with lens costs isn't a cheap way to learn) about how the different aspects of the lens interact.

The other thing i was wondering, i see adapters so you can use other manufacturers lens, is there anything that is fundamentally different about two seemly identical lens, eg 35mm format, 50mm f2.0 lens from different manufacturers, and what happens if you use them on a 4/3rds camera body.

And is there anywhere on the internet to get a decent grounding.

Okay, this may ramble a bit.

Small f numbers mean a bigger hole for the light to pass through, so you can use faster shutter speeds or lower ISO's for the same exposure. They also let the cameras autofocus work more easily and accurately as there's more light for them to work with. Not sure what you mean by "how the different aspects of the lens interact", can you be more specific?

It also means a shallower depth of field, so at f2.8 little is in focus, at f8, much more is in focus. Much beyond f13, you may start to get unwanted diffraction effects, but thats a different ball game altogether.

Adaptors may allow other lenses to be used, but you may not get full functionality (autofocusing metering etc). I'd look at 50mm f1.8 primes, as the bang for your buck you get with these lenses are unbeatable.

All lenses are different, some may be better than others, but they have been designed to work with a specific camera mount, so they expect the sensor to be in a certain position behind the mount. Using them on a 4/3rds body will give a crop factor of about 2, so your 50mm prime on your 4/3rds sensor will give you the same image as a 100mm lens on a full frame sensor.

The other rule of thumb is that a prime lens will give you a far sharper image at the same f numbers than a zoom at the same focal length unless you drop a fortune on pro zoom glass, and even then my 50mm f1.8 beats my 15x as expensive 24-70 f2.8 at 50mm at most apertures, and it goes to a wider aperture…

Hope that helps a little.

Get yourself over to http://www.talkphotography.co.uk for more info

or http://www.mu43.com for specific micro 4/3 info

andyl46 is right – although the 14-45 is very sharp – the 20mm 1.8 is sharper. It's great especially in low light but I use it for most things.

If you want to experiment and learn, you can pick up lots of old film camera lenses for cheap, and get adapters for the GF1 – you will have to manually focus and set aperture, but they will work in 'A' mode (as well as 'M'), so the camera can choose the shutter speed for you to try and get correct exposure.

There are threads on mu43.com with recommendations for old manual lenses – you might find it a pain to manually focus etc but I find it fun and enjoy the 'hands-on' aspect of it.

"how the different aspects of the lens interact",

All i am trying to say is if you change the focal length how does it affect depth of field, aperture settings, iso etc. I know what each means it is just the combining them bit.

On most zooms, including the Panasonic 14-45 – the maximum aperture you can use (lowest f number) gets smaller as you increase the focal length.

Have a read of this stuff for how the others relate to each other.

http://www.talkphotography.co.uk/forums/showthread.php?t=158332

As a general rule, the longer the focal length, the less depth of field you'll get at any given apperture.

Oh yeah, have a look at this

http://www.dofmaster.com/dofjs.html

Great link grum, must get some hyperfocal length tables printed.

To answer a question above, as the focal length gets shorter (towards the 18mm end of an 18-55mm kit lens say) your depth of field increases for a point in focus a fixed distance from the camera. The 55mm end focussed on the same point gives a much smaller DOF. This assumes the lens has a constant aperture at both those focal lengths, but as Grum rightly says, zooms tend to have smaller apertures at the longer end of their focal range.

They also let the cameras autofocus work more easily and accurately as there's more light for them to work with.

Generally true, but in the case of the MFT lenses the 20mm is significantly slower to AF than the 14-45.