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Author Topic: 24-840mm zoom  (Read 14172 times)

hsoftdev17

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24-840mm zoom
« on: September 26, 2010, 02:17:10 PM »
If they can make such a lens for the PowerShot SX30, how likely are they to make one as a self contained dSLR lens?  I own and enjoy using my Tamron 18-270mm superzoom and would frankly purchase a 24-840mm lens in a heartbeat.  I assume I'm not alone in this desire or such lenses wouldn't even exist.

I accept the minor image quality negatives of superzooms because I love the idea of lenses that serve the purpose of a half a dozen lenses.  It's wonderful to head out the door to take pictures and to simply know that I have, with one lens, every thing I need regardless of what I stumble upon to take pictures.

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24-840mm zoom
« on: September 26, 2010, 02:17:10 PM »

neuroanatomist

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Re: 24-840mm zoom
« Reply #1 on: September 26, 2010, 02:58:46 PM »
I...would frankly purchase a 24-840mm lens in a heartbeat.  I assume I'm not alone in this desire or such lenses wouldn't even exist.

Would you really "purchase...in a heartbeat" a lens that would likely cost somewhere north of $25K, be over 2 feet long, and weigh more than 15 pounds?  If so, I suspect you won't have much company.

The 24-840mm superzoom you mention is only possible because the size of the sensor in the PowerShot SX30 is less than 1/12th the size of even an APS-C (1.6x crop) sensor.  I suppose it might theoretically be possible to design a 24-840mm zoom for a dSLR - but for autofocus to function on non-1-series bodies it would need to be f/5.6.  Such a superzoom would be substantially larger than Canon's 800mm f/5.6L IS lens, which is already 19" long, weighs 10.5 pounds, and costs $11K.
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hsoftdev17

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Re: 24-840mm zoom
« Reply #2 on: September 26, 2010, 03:33:16 PM »
All certainly great points.  Until your comment, I was blissfully unaware that the SX30 was a 1/2.3" sensor.  There are a couple of things worth theorizing about however that would prevent a $25k price tag and a 17lb weight.  If an extender can easily double the focal length and weighs about a pound and is only a couple inches long, such a device being built in would not be out of the question.  Of course the trick then becomes the need of a 12mm zoom on the low end and a 2.8f on the high end.  Still nothing easy to accomplish of course at 420mm.  The thing to keep in mind I suppose is that the optical requirements of a superzoom, while important, are not the whole reason for owning it.  The Tamron 18-270mm has the noted problems of > 5.6f at 270mm (6.3f if i recall correctly) and minor image warping (fisheye) at 18mm.  While one of those problems does prevent the AF from working on most cameras, and the other produces "bent" images, it also doesn't take away from the lens' overall usefulness as an all in one.

I guess all I'm saying is that I would love to see the geniuses at Canon's optics department try to accomplish such a thing.  Or perhaps to provide extenders that go beyond 2x...  A 4x would be fantastic for example as long as it were crystal clear.  I would take the almost guaranteed loss of AF on nearly all lenses for that kind of reach.   :)


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Re: 24-840mm zoom
« Reply #3 on: September 26, 2010, 05:16:39 PM »
Actually, I think you will see super zooms in the future, but I think it will come from in-camera cropping (digital zoom) rather than the lens.

I think it's pretty clear from the Canon Concept Camera and from their announcement of the 120 mp APS-H sensor that we could see sensors in the future with sufficient resolving power to allow for radical crops without discernible loss of quality.

I'm repeating myself (from other posts) but I really think we will see a Canon SLR in the not too distant future that will give the user the option to crop in and use just a fraction of the sensor to extend the apparent focal length of a lens. 
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Flake

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Re: 24-840mm zoom
« Reply #4 on: September 27, 2010, 05:33:58 PM »
If you really would buy one 'in a heartbeat' then the 28 - 300mm IS L gets you to 300mm, and although they say it's not compatable with teleconverters you can get away with it if you're careful not to let the rear element collide with the TC.  That gets you to 600mm albeit at f/8 and a loss of autofocus on all but the 1D bodies.

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Re: 24-840mm zoom
« Reply #5 on: September 27, 2010, 06:32:22 PM »
I'm repeating myself (from other posts) but I really think we will see a Canon SLR in the not too distant future that will give the user the option to crop in and use just a fraction of the sensor to extend the apparent focal length of a lens.

I dunno about other brands but my Panasonic compact already does this and it drives me nuts. I can't shoot tele at less than full MP to save on memory space. If I wanted to crop, I'd do it in post!

That said, the 60D does have in camera post so I actually agree with your prediction. Just that like with scene modes, I don't really see the point of it other than to clutter things up.

severoon

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Re: 24-840mm zoom
« Reply #6 on: September 28, 2010, 05:08:13 PM »
@hsoftdev17 - "It's wonderful to head out the door to take pictures and to simply know that I have, with one lens, every thing I need regardless of what I stumble upon to take pictures."

I'm all for all-in-one lenses for special situations like travel where you have to have one inferior lens for an extended period of time, but on a session by session basis, I question whether the flexibility provided by such a lens would serve most photographers.

Many photographers buy gear as though the thing restricting them is not enough options, when in fact the root of their artistic limitations stem from too much flexibility and too many options. When this happens, it becomes tough for the average photographer to take full advantage of each corner of that capability.

For instance, have you ever shot at 400mm? I have (on a crop sensor, so actually 640mm equiv), and I find that it's critically important to use a good, solid tripod, remote release, and meticulous technique in all but the very brightest settings. The point is that when I'm heading out to do telephoto photography, it's a whole different experience than shooting in the sub-300mm range if I want quality work--so I can't really be flexible in this regard anyway just because I have a superzoom lens. And if I'm going to all that trouble to get quality tele shots, I certainly don't want to use a lens that's not optimized for that type of shooting.

Perhaps there is a future where there will be one lens to rule them all so that I'm not making quality trade-offs for the flexibility. In that case, bring it...I'm all for it. But given the physics wide apertures, light, sensitivity, and weight, I think we're bumping up against some fundamental limitations here.

"If an extender can easily double the focal length and weighs about a pound and is only a couple inches long, such a device being built in would not be out of the question."

I'd guess it is out of the question. Otherwise, a 200mm lens would just be a 100mm with a 2x built-in. The 400 would be a 100mm with 2 2x's built in? :-)

They don't do this for a very good reason: the extenders work by casting a larger image circle into the back of the camera (actually, they don't physically let the larger image circle pass, it effectively gets cropped away at the rear of the extender, but the principle is the same). If you're building a lens from scratch, it doesn't make sense to design it to throw the correct size image circle *before* adding the 2x. It adds design and weight and compromises image quality with no payoff.

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Re: 24-840mm zoom
« Reply #6 on: September 28, 2010, 05:08:13 PM »

lovemaker82

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Re: 24-840mm zoom
« Reply #7 on: October 05, 2010, 10:25:29 AM »
Guys, I currently own a Sony DSC TX1 point & shoot camera but I'm interested in exploring a DSLR camera. I'm looking at G12 and SX30IS.
While G12 has bad optical zoom and SX30 has an excellent one, I've heard controversial reviews of the 24-840mm lens. Would you suggest buying SX30 anyway since I'm a rookie when it comes to DSLRs or G12 would be better?

Thank you!

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Re: 24-840mm zoom
« Reply #8 on: October 06, 2010, 10:20:54 AM »
Guys, I currently own a Sony DSC TX1 point & shoot camera but I'm interested in exploring a DSLR camera. I'm looking at G12 and SX30IS.

Neither the G12 nor the SX30 are dSLRs - both are high-end point-and-shoot cameras.  The Canon dSLR lineup includes cameras like the Rebel T2i/550D, the 60D, the 5DII, etc.  Interchangeable lenses, optical viewfinder and a reflex mirror are hallmarks of dSLRs. 
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lovemaker82

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Re: 24-840mm zoom
« Reply #9 on: October 06, 2010, 10:31:56 AM »
Thank you, neuroanatomist.
I actually meant to ask about how good the 24-840mm lens are. I know that there are 18-55 and 18-200 lens. The cameras you've listed come with a low-end 18-55mm lens, that's why I don't wanna buy those cams. I don't wanna throw another $500-$700 for a decent lens with nice aperture that's why I'm leaning more toward the SX30.

Also, I'm not too anal about interchanging lens. Doesn't the SX30 have an optical viewfinder? I think it does. Also, I'm not too sure about what a reflex mirror is.
If only those 3 options set dSLRS apart from advanced point-and-shoot cameras then the SX30 would definitely be enough for me, but I wanna learn more about 24-840mm lens before I buy that camera.
« Last Edit: October 06, 2010, 10:40:54 AM by lovemaker82 »

neuroanatomist

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Re: 24-840mm zoom
« Reply #10 on: October 06, 2010, 12:26:15 PM »
If only those 3 options set dSLRS apart from advanced point-and-shoot cameras then the SX30 would definitely be enough for me, but I wanna learn more about 24-840mm lens before I buy that camera.

The image sensor is really what sets them apart.  The sensor in a T2i or 60D is 12 times larger than the sensor in an SX30.  That means much, much better image quality.  Now, if all you ever want to do is post images to a website or print 4x6" snapshots, you may be just fine with a P&S.   Other things set them apart, too - most P&S shoot at frame rates measured in seconds per shot, dSLRs shoot in the 3-10 shots per second range.  Bottom line, if you think an SX30 can deliver the same performance as a dSLR and a collection of quality lenses covering that focal range, you need to think again.  But, if your needs and your budget are a fit for the SX30, great.

There is no such thing as a 24-840mm zoom lens for a dSLR - as was discussed above, even if such a lens were possible, it would weigh several pounds and cost thousands of dollars (bigger sensor means bigger lens)

A T2i with it's low end 18-55mm lens will deliver much better optical quality than an SX30 within the overlapping focal range.  You see '24-840' but that's adjusted for comparison with full-frame/film cameras.  For the 'low-end 18-55mm' that equates to 29-88mm on the same scale (the real focal length of the 18-55mm is 18-55mm; the real focal length of the SX30 is 4.3-150mm).
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lovemaker82

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Re: 24-840mm zoom
« Reply #11 on: October 06, 2010, 12:49:29 PM »
How about comparing a SX30 to a reguler P&S? Lets say, as you've correctly mentioned, I don't have a budget big enough to afford a real dSLR and I'm not into professional photography either but I do wanna go above regular P&S and that's why I'm considering SX30. Maybe you could suggest an entry-level dSLR which would be better than SX30 but not as expensive as T2i? I love the fact that SX30 has an aperture of 2.8 and I like this feature alot. Even those lenses that come with T2i have an f of 3.5. I guess a professional photographer wouldn't be anal about this.
Wouldn't an image quality of SX30 be better than in a regular P&S camera?
« Last Edit: October 06, 2010, 12:51:18 PM by lovemaker82 »

neuroanatomist

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Re: 24-840mm zoom
« Reply #12 on: October 06, 2010, 02:23:22 PM »
I love the fact that SX30 has an aperture of 2.8 and I like this feature alot. Even those lenses that come with T2i have an f of 3.5. I guess a professional photographer wouldn't be anal about this.

Pro photographers are very anal about that.  Look at a very popular Canon dSLR lens line, the 70-200mm L zooms.  There's an f/4 version and an f/2.8 version of the image-stabilized lens, and the f/2.8 version costs twice as much.  The 300mm f/2.8L is 3x the cost of the 300mm f/4L, and the 85mm f/1.2 is five times the cost of the 85mm f/1.8.  So, with the 85mm prime I paid $1600 for that one stop of light to get f/1.2 vs. f/1.8, and my friend with the 300/2.8 paid over $3000 extra for that one stop of light.   So yes, aperture matters.

Regarding the SX30, first off it's only f/2.7 at the wide end - at the telephoto end it's f/5.6.  But really, it's not anywhere near f/2.7 if you're comparing it to something like a dSLR lens on a T2i. 

You are suffering from a common misconception about aperture as it relates to sensor size.  The 'crop factor' also applies to aperture, in terms of effect on depth of field.  Compared to full frame, a T2i has a crop factor of 1.6, and the SX30 has a crop factor of 5.6.  So, if you want to correctly describe the SX30's lens in terms of full frame equivalence, it has a 24-840mm f/15-31 lens.  So, f/2.7 on an SX30 is like f/15 on a full frame, or f/9 on a T2i.  So, that 'slow' f/3.5 on a T2i kit lens is a whole lot faster than the SX30. 

So, not f/2.7 but f/15.  I would guess that f/2.7 on the SX30 isn't sounding so good now... ;)

Canon clearly takes advantage of this misconception in their marketing - they state that the PowerShot S95 has a super-bright f/2.0 lens that is great for isolating the subject of a portrait.  They conveniently forget to mention that f/2 on the S95 gives the same degree of subject isolation as f/8 on a full frame camera, or f/5 on a T2i.   

The crop factor also applies to ISO noise, so for a given exposure, the pixel noise at ISO 200 on the SX30 is approximately equivalent to ISO 800 on a T2i, and equivalent to ISO 1250 on an a full frame camera like the 5DII.

Wouldn't an image quality of SX30 be better than in a regular P&S camera?

The SX30 is a regular P&S camera - it just has a bigger zoom range than most.  In general, superzoom lenses are not as good as lenses with shorter zoom ranges (same reason prime lenses - e.g. a 50 mm lens - have better image quality than most zooms).  A 35x zoom isn't even a superzoom, it's more like a supermegaultrazoom. 

Overall, something like the G12 or S95 will provide better image quality than the SX30 - bigger sensors, better lenses.
« Last Edit: October 06, 2010, 02:28:51 PM by neuroanatomist »
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Re: 24-840mm zoom
« Reply #12 on: October 06, 2010, 02:23:22 PM »

neuroanatomist

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Re: 24-840mm zoom
« Reply #13 on: October 06, 2010, 02:32:42 PM »
Maybe you could suggest an entry-level dSLR which would be better than SX30 but not as expensive as T2i?

Canon has a rebate on the Rebel XS - it's $500 with the 18-55mm kit lens, so that's only $70 more than the SX30.  Of course, you're giving up the telephoto zoom capabilities of the SX30.  You could get to 250mm for the Rebel XS with the EF-S 55-250mm for an additional $230 (and there may be a rebate on that lens later this month - Canon usually does lens/flash rebates in late October).

Or, you could consider buying a used Rebel - those are even cheaper than the SX30.
« Last Edit: October 06, 2010, 02:38:11 PM by neuroanatomist »
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Re: 24-840mm zoom
« Reply #14 on: October 06, 2010, 10:26:58 PM »
Quote
Would you suggest buying SX30 anyway since I'm a rookie when it comes to DSLRs or G12 would be better?

I'm afraid we are confusing you. Nothing has been said here that is incorrect, but I think it might help to step back a bit.

First, think about what you want to take pictures of, what your picture taking habits are and if those habits are likely to change. From what you've written, it sounds to me like you are interested in a "step-up" camera, but don't want to spend a lot of money.

It also sounds like you may not be particularly interested in lugging around a camera bag with three or four additional lenses and switching them out depending on what you are photographing.

What do you enjoy taking pictures of now? And, what do you think you will want to take pictures of in the future?

The SX30 sounds like a good camera for someone who enjoys birds, zoos and wildlife and wants to be able to zoom in as close as possible. The G12 is a great all-around camera for carrying around and being prepared to take a picture whenever one presents itself to you. If you want to take pictures of family, vacation pictures of scenery, cities, historic sites, etc., pictures of just interesting things you see on the street, the G12 is a good option.

The G12 is small, unobtrusive and the top of the Powershot line. The sensor is slightly larger than the SX30, it can produce high quality enlargements (within reason) and has many professional features.

There is a saying that "the best camera is the camera you have with you." You can't take pictures if you don't carry the camera around with you. If you're likely to view a DSLR as a hassle and a burden, then you are much better off with a "point-and-shoot." (As an aside, I find the phrase "point and shoot" a bit snobbish and frankly inaccurate. Almost any DSLR can be a "point and shoot" in fully automatic mode and cameras like the G12 have a full range of features that allow photographers to use them creatively.)

It's true that for not much more money you can buy a Digital Single Lens Reflex (DSLR), but you will be buying the bottom of the line DSLR vs. top of the line Powershot. That may be the right choice, but it may not.

The whole discussion of f-stops is confusing. It's not really fair to equate an f2.7 lens on the Powershot with a f15 lens on a Rebel. F-stops are format neutral in terms of exposure. An exposure that requires f5.6 at 1/125 of a second, is going to be the same no matter what camera and what format you are using.

I do not have the technical knowledge that some others on this forum have, but from what I have read here it sounds as though a small format camera will have greater apparent depth of field (the distance at which various objects will be in focus) at comparable f-stops. You might think that is an advantage, but it can be a disadvantage as well. Sometimes you want to separate the main subject from the background and that becomes harder with a small sensor and the greater apparent depth of field.

Something else to consider with the SX30 is that even with image stabilization, the longer a lens, the harder it is to hold it steady. Image stabilization helps, but zoomed out to 840 mm, you'll still need a fairly fast shutter speed to avoid shaky pictures.

Bottom line: go to your favorite electronic superstore and play with the cameras. Think about what you are looking for in a camera and how much you want to invest. Most DSLRs get updated every couple of years (some more frequently, some less) and the whole camera industry is undergoing rapid change, so any purchase you make today is likely to get replaced in a few years.  If you are not planning on buying additional lenses and don't want to spend a lot, you may be better off with either the SX30, the G12 or another upper level "point and shoot," even if you eventually decide to take the plunge with a DSLR.
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Re: 24-840mm zoom
« Reply #14 on: October 06, 2010, 10:26:58 PM »