Recently bought a Coolpix P900, love it.
We also have a DSLR. Looking at getting something with similar 'zoom' i've found myself a bit confused.
The P900 is a 24-2000mm equivalent (I haven't got my head around that yet) but it seems the the lens is 4.3-357mm. If I was to buy a lens for the DSLR would I be looking for 2000mm or (circa) 357mm?
Depends on the size of the image sensor in the DSLR. If its a true 35mm sensor, then you would need a 2000mm lens. If its the more common APS sized sensor then you get a magnification factor because the sensor crops the edges of the frame. The factor is typically about 1.4 to 1.6x, so you would need a lens in the 1200 - 1400mm range to get the same effect.
However for lenses that long, be prepared to pay an eye watering amount if you want anything of decent quality and also adequate aperture to actually let any light into it!
+1, and forget about hand-holding it, you will need a substantial tripod unless you are resting it on a solid object using a bean-bag.
The difference is because the target size is different. Measure the view angle you get with the P900 and then choose a lens designed for the DSLR with the same view angle. If the vendors of the lenses don't quote it google lens conversion table or something.
Bill
P900 sensor is (only) 6.2 x 4.6 mm compared to 22.2 x 14.8 for Canon APS-C.
So the factor is about 3.5 and you will need a 1200 mm lens for a Canon APS-C DSLR for the same telephoto view.
You won't of course get an 83:1 zoom ratio on a DSLR. The convenience of such a thing as found on a superzoom compact (or camcorder) comes at the price of quality.
Check out professional sports photographers and you will see that they carry several cameras with different lenses (often zoom, but the zoom ratio is seldom more than about 4:1).
From the early days of TV, lenses were always quoted as viewing angle - as different types of cameras had different target sizes. Never did understand why this wasn't done with photo lenses too. Even on the rare occasion where a lens will fit more than one type of camera.
But the quoted viewing angle would only apply to one target size...
Bill
2000 pronbaly.
Lenses still get quoted in '35mmm film equivalent'
Obviously a tiny CCD and a tiny lens will have the same angle of coverage as a much bigger lens and film area.
You will need a tripod or serious software to prevent [effects of] shake at 2000mm equivalent
Sssh. It's our dave. Socialism has entirely rotted his brain.
I'd like to see this for CCTV lenses, it would save a lot of effort, converting the focal length figures frequently quoted.
It *is* done, effectively, in that most cameras quote the 35-equivalent focal length of the lens, as well as the actual focal length. At least then you can compare lenses for different cameras by comparing their
35-equivalent focal lengths.
And you'll probably find that image-stabilisation, while good, doesn't work as well as the manufacturers claim - it is good but not perfect.
The thing I didn't realise about image stabilisation is that it can actually produce a *less* sharp picture if the camera is held rock-steady on a tripod: I found this when taking some night-time (ie 10 second exposure) photos with my compact camera, until I worked out in the menu how to turn off IS. On my DSLR it was easy: there was a big IS on/off switch on the lens!
But how many lenses can be fitted to cameras with different target sizes?
Not saying you wouldn't give the actual focal lenght too - but stating the angle of view for each target size camera the lens would fit to wouldn't be difficult?
In other words, if the norm was to state the angle of view, you'd know what to expect with that in use. Across all platforms. Those who wanted to know the actual focal lenght could look it up.
We should drop this "35mm equivilant". Many digital cameras users have never used a 35mm camera. We should use "Angle of view" as a format independant reference.
Quite. And I doubt the movie film 35mm target size has any real relevance to digital cameras.
The trouble is, it isn't format independent, is it?
You'd need to standardise on which dimension you were referring to: horizontal, vertical or diagonal. Probably best to use diagonal then a) you are using the same convention as when specifying screen sizes for TVs and laptops, b) you don't have the added confusion that the long axis is vertical in a portrait picture and horizontal in a landscape picture.
I suppose you've got the added problem that the numbers would probably involve fractions of a degree so these may need to be marked on the lens barrel - unless you round to the nearest degree.
Was it only for TV work that lenses quoted in angles were used? In 16mm and
35mm movie and 35mm still, lenses are usually referred to as actual focal length. (NB: 35 mm movie and 35 mm still are different size frames: 18x24 for movie and 24x36 for still, because the film runs vertically in movie and horizontally in still, so the distance between perforations is the long axis in one and the short axis in the other)The Natural Philosopher wrote in news:oct9qg$2k6$1 @news.albasani.net:
The user would know if the lens that matched his camera / sensor has a particular view angle and from that be able to imagine the field of view that would be achieved.
The reason angle of view was used in TV in the early days was there were different types of electronic camera in use. And someone planning say a drama wouldn't always know which studio he's get and therefore which type of camera. So he could work out is shots on paper using angle, and leave it to others to make sure the correct lenses were fitted to the appropriate camera - long before the days of zoom lenses being the norm.
IIRC, the standard lenses on a studio TV camera turret in those days were a 35, 24, 16 and 8 degree.
Does anyone know or care what focal lenght lens is fitted to their phone? But they will be more aware of its angle of view, through using it. Same as with any camera. Which is why, to me, it is the more important thing to quote.
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