500 mm lens
 

Hi all

Have been looking at lens in the magazines, see when it just says 300 or 500 etc does that mean they are fixed at that range. in which case would i be better looking at something like a 150 - 500mm.

Sorry if its a stupid question just cant quite get my head round it.

Thanks in advance.

Andrew

Depends whether you want a prime (fixed focal length) or a zoom where the focal length is variable like the 150-500mm. In general prime lens give better IQ and take converters better whereas the zoom is more flexible. For birding the very best lenses are primes but they are also more expensive. Another thing to consider is the speed of the lens, where a f2.8 is considered fast and a f5.6 is considered slow. As far as light goes a f4 lens will let in twice the amount of light that a f5.6 would but only half the amount that a f2.8 lens would give you.
Hope this helps Andrew.

Hi Andrew, Yes, when a lens is described as a 500 mm or 300 mm it is fixed focal length. A 150-500 is a zoom with varied Focal Length. Roy's advice is something else you need to take into consideration - the f stop controls the amount of light getting to the sensor or film. I use a 1000 mm Reflex Nikkor which is fixed at f11. This means I only use it on very bright and relatively static subjects if using it for birds. If birds are in motion I use a 500 mm f4 -P Nikkor which is a lot "faster". I also only use both from a firm tripod.

Hi Guys thanks for the help the 150 - 500mm lens i was looking at is f5 - f6.3 is that reasonable for regular use as long as it is not to dark.

Andrew

The super-tele zooms like the Sigma 150-500 OS and the Tamron 200-500 and good versatile lenses that give good reach and a nice range of focal length. The downside is that they are slower focusing than the big primes and tend to not have as good image quality, especially when shooting wide open. In good light they can perform very well but as soon as the conditions get worse they struggle. The zooms offer a relatively cheap way to get long focal lengths, as long as you work within it's limits you should do well with one.

Hi does the Sigma 150-500 OS and the Tamron 200-500 lens give the same sort of results or is one a better quality than the other.

Andrew

Having never used either I cannot say but the Sigma has a 4 stop OS (image stabilisation) whereas the Tamron has not.

Some general points.......

The problem is that with (relatively speaking) cheaper lenses, they don't give their best results when used wide open. Even if your technique is perfect, a budget zoom wide open will give relatively soft images especially if used at max zoom. To get the best out of these lenses, you will have to stop down a bit to f/8 or even f/11 and pull the zoom back a bit from its max reach. At this point, you're starting to need a lot of light.

Of the two, while having no experience of either, I would go for the Sigma as it has the OS image stabilisation which is very useful if you want to hand hold. I had the old Sigma 170-500 which is probably not as good as the 150-500 but on a reasonably bright day gave pretty good results as long as it was on a sturdy tripod. For the money I don't think you could do better than the Sigma 150-500.

Cheers guys going to edinburgh next week so im hoping to find one to have a look at before i make up my mind.

Andrew