Matt.H
Member
Registered: 12th Mar 03
User status: Offline
|
Was at work today and was chatting to a bloke i work with as he was looking for a new lens for his camera. Im also wanting to do the same. I have a standard lens but looking for something longer. Basically something for me to get some good pics at airshows etc. He was telling me that you divide the higher number into the lower number to give you the lens magnification. For example a lens thats 18-200mm would give you 11x optical zoom whereas a 70-300mm would only give you just over 4x. Could someone clarify this and if its true which would be the better lens to go for for what I want to use it for.
|
AndyKent
Member
Registered: 3rd Sep 05
User status: Offline
|
Is true, but completely meaningless.
If you want a lens for airshows, you need something with 300mm at the long end absolute minimum. 400mm would be better.
|
John
Member
Registered: 30th Jun 03
User status: Offline
|
x zoom is used on compact cameras and is pretty meaningless there, even more so with an slr.
Totally depends on what you want to do with it and as Andy says, longer the better for airshows.
|
deano87
Member
Registered: 21st Oct 06
Location: Bedfordshire Drives: Ford Fiesta
User status: Offline
|
I have quite a cheap Tamron 70-300mm lens - came in a deal with my Canon EOS 450D. Does the job and gets pretty good results.
All with that lens on an overcast day.
|
Matt.H
Member
Registered: 12th Mar 03
User status: Offline
|
Just wondered if you could explain why it is meaningless when it comes to dslr's. Just after a better understanding that's all.
|
Matt L
Member
Registered: 17th Apr 06
User status: Offline
|
problem with big lenses is the fstop number and how slow they are to react unless you pay a pretty penny for a lense.
eg the entry level 70-300's like sigma/tamron ones are good but not really good enough for airshow stuff as the fshtop at the 300mm is quite high coupled with the high shutter speed you will need may not give you decent pictures aswell as the focusing speed of them may not be that good.
also when i had the sigma one the fringing on the images was quite bad at 300mm but that could be a bad lens example.
as said you could do with something that is 200-400mm and with as low a fstop as possible and one that doesnt take ages to focus.
|
AndyKent
Member
Registered: 3rd Sep 05
User status: Offline
|
Meaningless because its just a number.
Imagine I had two lenses - a 1 to 400mm (so 400x zoom) and a 400mm non-zoom (zero zoom).
If you take a picture of something using both lenses at 400mm, the object would come out the same size. Its the mm length that matters. Manufacturers of pocket cameras get away with it because most people won't be able to compare mm focal lengths. On fairly standardised DSLRs you always go by mm.
|
Scotty_B
Member
Registered: 11th Jun 03
Location: East Kilbride
User status: Offline
|
A lens that has less zoom range almost always performs better.
The 70-300VR will kill an 18-200 between 70-200mm. Focusing is always fast and never hunts.
|
Ian
Site Administrator
Registered: 28th Aug 99
Location: Liverpool
User status: Offline
|
The magnification factor is relevent, as it demonstrates how versitile a lens is.
So the 18-200 which has an 11x zoom factor would be good for a lot of situations, wide angle when you need it and a bit of reach when you want that.
Trouble is, such a lens wouldn't be particularly good quality. There are a lot of compromises in having such a wide zoom range and it wouldn't take as sharp a photo as, for example a dedicated wide angle lens or a dedicated telephoto lens.
Same reason people use prime lenses. They're obviously not as versitile as a zoom lens but they're also generally far better quality for the money/weight/complexity etc.
If you want a case in point, check out the Canon 28-300mm f3.5-5.6 L -
http://www.the-digital-picture.com/reviews/canon-ef-28-300mm-f-3.5-5.6-l-is-usm-lens-review.aspx
quote:
Not unusual for a super-zoom lens is distortion and distortion is indeed one of the Canon EF 28-300mm f/3.5-5.6 L IS USM Lens' weaknesses. Barrel distortion, at 28mm, is very strong.
quote:
The Canon EF 28-300mm f/3.5-5.6 L IS USM Lens has CA (Chromatic Aberration) in the full frame corners from 28mm up to about 50mm and again at 300mm. Moderate vignetting is also apparent in this focal length range - widest (less than 35mm) and longest focal lengths are the worst.
quote:
This is a super-zoom lens. Creating such a lens with perfect image quality in a package that is affordable and carryable by mortals is proven impossible as of this review date. If you want all of those focal lengths in one lens, you must accept a compromise.
You can't overlook that it's a handy lens and it does save you carry and changing during differing circumstances. But it is a compromise.
|
Ian
Site Administrator
Registered: 28th Aug 99
Location: Liverpool
User status: Offline
|
Also on compact cameras, you'll generally see this measurement rather than "proper" focal lengths because they will generally all be similar at the wide end, therefore the zoom factor is an indicator of how much reach you have at the long end.
Telephoto, which you may already be starting at 70mm+ becomes less important, a 4x zoom starting at 100 for example, has more reach than the 10x starting at 30mm.
|
Matt.H
Member
Registered: 12th Mar 03
User status: Offline
|
Ok cheers for the info. made it a little clearer. So say for the instance I'd like to be using it in, what lens would you recommend without the price going silly? I have the standard kit lens and not to bothered about having to swap over for static stuff. Its just frustrating when you cant even get close enough to get a decent shot whilst planes are in the air.
|
Matt L
Member
Registered: 17th Apr 06
User status: Offline
|
what camera do you have for starters?
|
Daveskater
Premium Member
Registered: 29th Apr 08
Location: Oxford, UK Drives: Jap wagon
User status: Offline
|
quote:
Originally posted by Ian
So the 18-200 which has an 11x zoom factor would be good for a lot of situations, wide angle when you need it and a bit of reach when you want that.
You can't overlook that it's a handy lens and it does save you carry and changing during differing circumstances. But it is a compromise.
Exactly, I rented an 18-200mm for PVS and TVL and it was ideal as I could get shots of stands and then shots of the track without having to change lenses over every 10 minutes.
Numberwang!
Originally posted by AlunJ
I like you Dave, you are a man of men
Originally Whatapp'd by Neo
Dave's maybe capable of a drive-by cuddle
Look at my pictures
|
Scotty_B
Member
Registered: 11th Jun 03
Location: East Kilbride
User status: Offline
|
The 18-200mm is a compromise lens and will satisfy 95% of amateur togs.
I hate changing lenses, so I bought a 2nd body, problem solved. 
|
Matt.H
Member
Registered: 12th Mar 03
User status: Offline
|
I have a Canon 1000d.
|
Ian
Site Administrator
Registered: 28th Aug 99
Location: Liverpool
User status: Offline
|
Changing lenses is one of the biggest things you notice about moving to a proper SLR, it is a question of planning where you're going and not just walking somewhere and thinking 'I need xx mm', you'll get in the habit of it.
And to echo most thoughts, yes the lens in question would be suitable for the majority of situations in terms of ability and quality.
|
AndyKent
Member
Registered: 3rd Sep 05
User status: Offline
|
I'm not a massive zoom fan to be fair, though I do own two zooms, and three primes.
You can tell the difference in image quality, though it is slight, it is noticable if you look closely. I like the inflexibility of primes though, they make you work for a picture rather than just zoom-click-zoom-click.
|
Gareth F
Member
Registered: 16th Jan 08
Location: Location Location
User status: Offline
|
Im going to India so will be using the 350d alot, what kinda things should i look into.
Batterys, new lense hoods etc
Got the kit 18-55mm lense but what would be better for animal shots?
|
Ian
Site Administrator
Registered: 28th Aug 99
Location: Liverpool
User status: Offline
|
Depends how big their teeth are. Generally larger teeth need a longer lens.
|
Gareth F
Member
Registered: 16th Jan 08
Location: Location Location
User status: Offline
|
Like the way you put that 
|
smcGSI16V
Member
Registered: 26th May 03
Location: Farnborough Drives: Thurlby 888 CDTi No.98
User status: Offline
|
Taken on a Canon 1000d with a Tamron 70-300mm
http://i108.photobucket.com/albums/n16/scgsi16v/Airshow%202010/DPP_00534.jpg[/IMG]]
[Edited on 19-12-2010 by smcGSI16V]
[Edited on 19-12-2010 by smcGSI16V]
|
Daveskater
Premium Member
Registered: 29th Apr 08
Location: Oxford, UK Drives: Jap wagon
User status: Offline
|
quote:
Originally posted by Ian
Depends how big their teeth are. Generally larger teeth need a longer lens.
[Edited on 20-12-2010 by Daveskater]
Numberwang!
Originally posted by AlunJ
I like you Dave, you are a man of men
Originally Whatapp'd by Neo
Dave's maybe capable of a drive-by cuddle
Look at my pictures
|
deano87
Member
Registered: 21st Oct 06
Location: Bedfordshire Drives: Ford Fiesta
User status: Offline
|
My Tamron 70-300mm is shocking on auto focus. Sometimes it doesn't work.
|
