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View Full Version : Optical zoom and digital zoom?


CaptainCaveMann
Dec 13, 2004, 06:02 PM
Whats the difference between optical zoom and digital zoom?

jxyama
Dec 13, 2004, 06:19 PM
optical zoom means the camera lens is actually used to zoom in on the objects. you will see more "real" details because the optics of the camera is physically changed to collect more information.

digital zoom means "zooming" on the pixels. no details can be enhanced, as there's no additional information being collected by the camera. think of it as cropping the image and enlarging the cropped image so that it's still the same size.

basically, ignore any claims about the digital zoom. it doesn't help you take better pictures - whatever you see by digitally zooming, you can replicate later via cropping/enlarging using a software.

vtprinz
Dec 13, 2004, 06:28 PM
As was said above, ignore the fact the a camera even has digital zoom. With each little increment of digital zoom, you lose a good amount of quality in the picture. Stick with optical zoom. Digital can be used in emergencies, but again as said above, you can always crop and enlarge the portion you want on the computer, and you get much better quality that way.

FWIW, I work at Ritz Camera, and we even tell our customers not to use digital zoom.

CaptainCaveMann
Dec 13, 2004, 06:42 PM
As was said above, ignore the fact the a camera even has digital zoom. With each little increment of digital zoom, you lose a good amount of quality in the picture. Stick with optical zoom. Digital can be used in emergencies, but again as said above, you can always crop and enlarge the portion you want on the computer, and you get much better quality that way.

FWIW, I work at Ritz Camera, and we even tell our customers not to use digital zoom.Ok got it cause i need a lot of optical zoom because we film events from about 100 yards away

vtprinz
Dec 13, 2004, 06:54 PM
Ok got it cause i need a lot of optical zoom because we film events from about 100 yards away

Ouch, that could require a pretty good amount of zoom. And that means $$

You can test some cams out in a store, but I doubt you'll get a lens that can get close enough without going into the DSLR category.

CaptainCaveMann
Dec 13, 2004, 07:33 PM
Ouch, that could require a pretty good amount of zoom. And that means $$

You can test some cams out in a store, but I doubt you'll get a lens that can get close enough without going into the DSLR category.Well me and my friend were using a 10x zoom and it wasnt really cutting it but u could still see but im hopin 18x or 20x will do it on the newer cams

vtprinz
Dec 13, 2004, 07:34 PM
just came across this, thought you might like to see it: http://bobatkins.photo.net/photography/digital/digital_zoom_vs_optical_zoom.jpg

I take no credit for the shot, I just found it in google. So if it's yours, don't sue :o

CaptainCaveMann
Dec 13, 2004, 07:49 PM
just came across this, thought you might like to see it: http://bobatkins.photo.net/photography/digital/digital_zoom_vs_optical_zoom.jpg

I take no credit for the shot, I just found it in google. So if it's yours, don't sue :oThanks man that helps out

Mechcozmo
Dec 13, 2004, 09:06 PM
Don't use digital zoom. You don't gain quality.

Optical zoom is the best way to go, along with a high megapixel count.

I'd say you might need a telephoto lens... but it depends on quite a bit.

Earendil
Dec 13, 2004, 09:57 PM
Ok got it cause i need a lot of optical zoom because we film events from about 100 yards away


That's a pretty good distance. It depends on what you are taking pictures for. I take pictures for my College paper, which are printed Black&Wh
ite and in pretty pixilated quality. I use a Fuji s5000, which is a Semi-SLR (or SLR like camera), and attach a Raynox 1.54 magnifier. The lens on the camera is a 37-370mm (35mm equiv), and with the Raynox my reach extends to about 570mm, enabling me to take decent shots (minus blur) for a black and white paper. But once you tart talking shooting over that much distance with that much power, you need to think about a tripod as well (and for boring events, consider an iPod ;))

The Fuji s5000 is a 4mp camera, and can be had around the net for 300-400, and the Raynox magnifier for another $100. In todays market, if you don't already have SLR lenses, and can't drop $2000 for a good DSLR and a long lens, the Semi-SLR perform nice for their price.

Peace,
Tyler

CanadaRAM
Dec 14, 2004, 01:52 AM
At long zooms, you need a super solid tripod - every jiggle of the camera translates into 10x the motion in your shot.

Failing that, look for a camera with an anti-shake mechanism, which rapidly adjusts the optics to counteract movement of the camera. The Minolta Z3 is one. You have a specialty requirement -- Hit the serious camera review sites like www.DPReview.com and www.Steves-digicams.com

Thanks
Trevor
CanadaRAM.com

absolut_mac
Dec 14, 2004, 03:18 AM
Whats the difference between optical zoom and digital zoom?

The picture came from this Digital Photography Primer....

http://www.photo.net/equipment/digital/basics/

This is really an excellent site for in-depth equipment reviews, especially the user comments that follow, and a great place to learn about technique and composition.

http://www.photo.net

cluthz
Dec 14, 2004, 06:28 AM
Ok got it cause i need a lot of optical zoom because we film events from about 100 yards away

20x zoom in a film camera isn't so uncommon, I think most people here are talking about photos, not film.

If you are going to film with 20x zoom you'll need a camera with a good optical stabilisator and a good tripod. Handheld camera with 20x zoom is a disaster...

It's also important where the zoom starts.. If you get a 10x 12-120mm (compared to 35mm film) you'll have a great wideangle, but a lousy tele. 50mm (35 mm) is a normal objective (1:1), and therefore a 100mm will be 2x.
If the widest angle of your camera is say 24mm then 48mm will be 2x.
What you need is a highest possible mm compared to 35 mm film.
a 10x 40-400mm has a better tele than a 20x 18-360mm (but a horrible wideangle..)

Jo-Kun
Dec 17, 2004, 07:44 AM
So you're filming... motion... no stills...

ok as told above DigitalZoom is ****

You might consider (according to budget etc.) to get the Canon XL2 with an adaptor you can use normal Photo EF Objectives on this one... and get those with image stabiliser... for instance since you're only shooting tele: the 100-400 F4.5-5.6 with image stabiliser (you can even buy the non-zoom 600mm f4 with image stabiliser...) and you can even get an 2x extender... so 1200mm is big enough?

ok you'll need a big budget... but I think this is the best quality you can get optically (better than frontles extenders for existing camera's... because any objective on itself is better than those extenders in most ways...

J

superninjagoat
Dec 17, 2004, 11:06 AM

superninjagoat
Dec 17, 2004, 11:06 AM
Good information given above, so I'll try to to repeat. However, you need to consider a couple of other things.

1. Pixel dimensions of your camera: If you are only going to be using these pictures at lower resolutions (say 200 pixels per inch or below), you can get a 5 megapixel camera with digital zoom and really not worry about image quality (provided you're not running the image at three feet by 5 feet). And the in-camera zoom can help you compose your shot better.

2. The other thing to look at, if you do decide to go with the optical zoom (which, as stated above IS better), is the aperture range of the lens. Basically, aperture is the size of the pinhole in the camera that allows light to hit the film (or CCD). The smaller that size, the less light makes it onto the film. The smaller the aperture number, the more light it let in. Every time you double the number (from f1.4 to f2.8, for example), one quarter of the light is let into the camera.

So, if you have a 200mm - 800mm zoom lens with an aperture range of 2.8 - 12.X, your shots at 800 could potentially be dark with poor contrast compared with shots at 200mm.

All this is to say, all things being equal between two zooms, pick the one with the smaller high-end aperture (f-stop) number.

Jo-Kun
Dec 17, 2004, 11:25 AM
some corrections IF you're talking about photography instead of video...

the contrast between an image shot at F2,8 or F11 IS the same (if off course you do change the schutterspeed accordingly :p) the difference is the depth of field...
If you need fast speeds: use the big opening (low number) if you need more depth of field use the smaller opening (higher number) but consider that is some cases you'll need a tripod or image stabiliser to provied non-shaken images...

the big difference is the image you'll get in the viewfinder since off course F2,8 lets more light in the camera than f5,6 for instance... so if you shoot in very dark condidtions getting a lens with a bigger opening is the way to go... but when you shoot the image you'll select the F number and speed according to the result you want...

what is the best F number to use any lens on? the number stated on the lens (lets get back to F2,8) and close it 2 'stops' thats the ideal F number for any lens...

arogge
Dec 17, 2004, 10:42 PM
so 1200mm is big enough?J

I want one of these (http://cakonos.image.pbase.com/image/35670190.jpg).

el greenerino
Dec 20, 2004, 05:50 AM
I want one of these (http://cakonos.image.pbase.com/image/35670190.jpg).

I'd like to use that with a 2x magnifier... 2400mm muh hahahaha

CaptainCaveMann
Dec 20, 2004, 11:28 AM
Im only talking about video sorry

absolut_mac
Dec 21, 2004, 04:00 AM
Im only talking about video sorry

What difference does it make whether you're talking about a still camera or video? Either way the image degradation will be the same.

The only difference is that it will be more easily seen with a still camera than in a video for two main reasons viz. video pics are lower resolution than most still cameras and because the picture on the screen is moving, so it's lower resolution will not be as obvious.

The bottom line is that digital zoom will degrade the picture, regardless of whether it's a video pic or not.

superninjagoat
Dec 21, 2004, 07:04 PM
What difference does it make whether you're talking about a still camera or video? Either way the image degradation will be the same.

I think you answered your own question.

The only difference is that it will be more easily seen with a still camera than in a video for two main reasons viz. video pics are lower resolution than most still cameras and because the picture on the screen is moving, so it's lower resolution will not be as obvious.

Since he will be doing video, the degradation will be less noticeable. After a certain point, CaptainCaveMann doesn't care what the image quality is, because at that point the picture is good enough.

CaptainCaveMann,
one way you can judge what combination of digital/optical zoom you need would be to start with the output resolution you intend to use your footage. Say it is 640 X 480. Let's also assume you want 20X magnification. If you have a camera with 3.2 megapixels (2048x1536), you could use up to 3.2 times digital zoom without significantly messing with your image quality (2048 / 640 = 3.2). You would need at least 17X optical zoom to make up the rest of the 20X zoom.

This assume that you are using a camera with digital zoom technology that zooms in on the picture as it digitally zooms, effectively cropping out the outside picture data. Some less expensive cameras simply "blow up" the pixels, which would degrade the image some. I'm familiar with Sony's digital cameras, which typically use the first of these two methods.

And as others have pointed out, at the zoom level you're talking about, a good image stabilization system in your camera should be your biggest concern. Even "blown out" footage is better than footage that is all over the place.

CaptainCaveMann
Dec 21, 2004, 07:21 PM
I think you answered your own question.



Since he will be doing video, the degradation will be less noticeable. After a certain point, CaptainCaveMann doesn't care what the image quality is, because at that point the picture is good enough.

CaptainCaveMann,
one way you can judge what combination of digital/optical zoom you need would be to start with the output resolution you intend to use your footage. Say it is 640 X 480. Let's also assume you want 20X magnification. If you have a camera with 3.2 megapixels (2048x1536), you could use up to 3.2 times digital zoom without significantly messing with your image quality (2048 / 640 = 3.2). You would need at least 17X optical zoom to make up the rest of the 20X zoom.

This assume that you are using a camera with digital zoom technology that zooms in on the picture as it digitally zooms, effectively cropping out the outside picture data. Some less expensive cameras simply "blow up" the pixels, which would degrade the image some. I'm familiar with Sony's digital cameras, which typically use the first of these two methods.

And as others have pointed out, at the zoom level you're talking about, a good image stabilization system in your camera should be your biggest concern. Even "blown out" footage is better than footage that is all over the place.I have no idea :confused: Heres the deal... Me and my friend sit up on top of this hill at the beach and we want to film eachother surfing and make a video. I have no clue what we need or what not but we were using my friends camera and it only had 10x zoom and it looked fine but it was just to far away. I will be editing it on a 1024x768 screen if that helps?? My friend has a powerbook and i think thats 1200x800 screen or something like that so i hope that answers the resolution question you asked. I was hoping the 350 dollar camera from cannon with 20x zoom would do the job. Were not rich and were also not looking for extremely good quality we just want to watch ourselves surf and make a decent video that is clear enough to see.

superninjagoat
Dec 21, 2004, 07:25 PM
I have no idea :confused: Heres the deal... Me and my friend sit up on top of this hill at the beach and we want to film eachother surfing and make a video. I have no clue what we need or what not but we were using my friends camera and it only had 10x zoom and it looked fine but it was just to far away. I will be editing it on a 1024x768 screen if that helps?? My friend has a powerbook and i think thats 1200x800 screen or something like that so i hope that answers the resolution question you asked. I was hoping the 350 dollar camera from cannon with 20x zoom would do the job. Were not rich and were also not looking for extremely good quality we just want to watch ourselves surf and make a decent video that is clear enough to see.

PM me a still from the video. See if you can't find one that you think was taken at the full 10X zoom. I'll see if I can help you. s.n.goat

superninjagoat
Dec 21, 2004, 07:36 PM
I'm assuming that you don't necessarily want to watch yourselves in Hi-Definition format. Digital TV is 640 by 480, which is slightly higher than what actually can be displayed on a typical television. 640 x 480 = 307,200, which is about half of the 680,000 pixels on the Cannon video camera to which you are referring. That means you could get about 40x zoom without screwing things up. That means your surfer would be about four times larger that what you were able to capture with your previous camera.

rickvanr
Dec 21, 2004, 08:32 PM
which format are you looking at?

digital 8 or Mini DV? Digital 8 camera's have bigger bodies, which means more zoom. $300 USD for a Sony Digital8 with 20x optical zoom as compared to Sony's Mini DV which have 10x or 12x zooms and cost much more.

CaptainCaveMann
Dec 21, 2004, 09:32 PM
I think canon has one thats mini dv for about 400 bucks