Conventional Thinking

[jcuknz]

My impression of this is regard to zooms is that any zoom of greater range than three is going to have compromises involved in its design and manufacture .... I'm thinking that my x10 zoom must be seriously deficient, not that I have noticed this in any way ... but then I come upon a rave review of the latest Panasonic HD video camera which has a x50 zoom .... makes me wonder about CT!

[rpcrowe]

Video cameras as well as old 16mm film cameras have smaller formats than even a crop DSLR. It is easier to design a zoom lens to cover these small formats than it is to design a zoom lens which will effectively cover the relatively larger crop formats or especially full frame formats.

In the mid-1960's when the only zoom lens for 35mm film still cameras was the horrible 43-86mm Nikon, I was using an excellent 12-120mm f/2.5 Angenieux zoom lens on my Arriflex 16mm motion picture film camera for professional cinema work. The Angenieux provided top-notch IQ and was a 10x zoom.

OTOH: one has to be careful when an extended zoom lens is advertised by a manufacturer. Often these zooms are digital, not optical zooms. What they do is to crop the center portion of a image to give the effect of a longer zoom range.

Panasonic calls their digital zoom "Intelligent Zoom" while their optical zoom is called just that! I use a Panasonic HDC-TM900 camcorder, which was one of the top-line consumer camcorders from Panasonic when I purchased it last year, has a 12x optical zoom and a 20x "Intelligent" zoom.

Panasonic HC-X920 3MOS Ultrafine Full HD Camcorder which is one of the top line consumer camcorders on the B&H site and is listed as having a 12x Optical Zoom Leica Dicomar Lens and has a 40x "Intelligent" zoom.

I would guess that since the more expensive of the consumer camcorders are equipped with 12x optical zooms, that these lenses are likely superior to the lenses for lower cost Panasonic camcorders such as the Panasonic HC-V520 which costs about a third of what the HC-X920 sells for. The HC-V520 has a 50x Optical zoom and an 80x "Intelligent zoom.

BTW: my 12x zoom is plenty for me and I have never ventured into the "Intelligent Zoom" world!

[Manfred M]

Nikon and Canon's pro lenses (f/2.8 24-70mm and f/2.8 70-200mm) both have a zoom factor of less than 3. Coincidence? I think not.

[Colin Southern]

Nikon and Canon's pro lenses (f/2.8 24-70mm and f/2.8 70-200mm) both have a zoom factor of less than 3. Coincidence? I think not.

Although we also have the 24-105 & 100-400.

Generally, I'd say once you get past 3:1 to 4:1 you're starting to push your luck, especially if the short end is tending towards wide angle.

[jcuknz]

Further investigation reveals it is 21 optical .... still a long way from three and it is a 28mm at the wide end so not that small .. the Angenuiex I had was not that small ... but perhaps they are talking about 'equivalents' to muddy the water.

[Glenn NK]

Although we also have the 24-105 & 100-400.

Generally, I'd say once you get past 3:1 to 4:1 you're starting to push your luck, especially if the short end is tending towards wide angle.

I'd agree with this.

I've seen several mentions by other knowledgeable photographers that 4:1 is about the limit for a good lens, and I'd suspect that for an excellent lens the ratio is less.

The Canon 24-105 is usually referred to as a good lens, but not excellent (4.38).

The Canon 100-400 is also a good lens (4:1)

The Canon 70-200 f/2.8 (Mark II) is considered to be an excellent lens (2.86:1)

I have a 17-55 EF-S. It's getting pretty close to excellent optics (3.24:1)

As Manfred said, "coincidence? I think not".

Glenn

[Colin Southern]

I'd agree with this.

I've seen several mentions by other knowledgeable photographers that 4:1 is about the limit for a good lens, and I'd suspect that for an excellent lens the ratio is less.

The Canon 24-105 is usually referred to as a good lens, but not excellent (4.38).

The Canon 100-400 is also a good lens (4:1)

The Canon 70-200 f/2.8 (Mark II) is considered to be an excellent lens (2.86:1)

I have a 17-55 EF-S. It's getting pretty close to excellent optics (3.24:1)

As Manfred said, "coincidence? I think not".

Glenn

It'll be interesting to see if liquid lens elements are a game-changer in this regard.

[Colin Southern]

I'd agree with this.

I've seen several mentions by other knowledgeable photographers that 4:1 is about the limit for a good lens, and I'd suspect that for an excellent lens the ratio is less.

The Canon 24-105 is usually referred to as a good lens, but not excellent (4.38).

The Canon 100-400 is also a good lens (4:1)

The Canon 70-200 f/2.8 (Mark II) is considered to be an excellent lens (2.86:1)

I have a 17-55 EF-S. It's getting pretty close to excellent optics (3.24:1)

As Manfred said, "coincidence? I think not".

Glenn

It'll be interesting to see if liquid lens elements are a game-changer in this regard.

[krispix]

I'd agree with this.

I've seen several mentions by other knowledgeable photographers that 4:1 is about the limit for a good lens, and I'd suspect that for an excellent lens the ratio is less.

The Canon 24-105 is usually referred to as a good lens, but not excellent (4.38).

The Canon 100-400 is also a good lens (4:1)

The Canon 70-200 f/2.8 (Mark II) is considered to be an excellent lens (2.86:1)

I have a 17-55 EF-S. It's getting pretty close to excellent optics (3.24:1)

As Manfred said, "coincidence? I think not".

Glenn

40 or so years ago Nikon had a range of zoom lenses. 28-45mm, 43-86, around the 2:1 range and all were considered sub-par. No pro would look at one twice.
In the intervening years the technology has advance tremendously and, as suggested here, ranges of 4:1 are considered very good or excellent. There's no reason to suppose that in a few more years 6:1 will not produce top quality images, then 8:1 etc. etc.
I'm not sure that the zoom range is the whole story. My 18-200mm 'walkabout' (11:1) produces very slightly better images than my 10-20mm (only 2:1) which would indicate that the focal length has something to do with it.
However, never doubt the ability of human engineering to constantly improve. I predict that in another 20 years (I may not be here to see it, but many of you will) you'll be wondering if 20:1 is the limit of zoom technology.

[ajohnw]

My recollection of the 70-80's period is that Nikon offered one zoom lens. Maybe at some point in the 80's they may have introduced more It did sell too despite the cost.

I've mentioned the 3:1 range a number of times as it's a good rule of thumb. At 4:1 things vary but typically drop off at the long end. Wide angle quality zooms seem to even have problems at 3:1

Movie cameras of one sort or another confuse things. 2 factors. Resolution is relatively low and things get easier in many ways as optics get smaller. The best example of the latter is microscope objectives. Those do get near being diffraction limited. Best example of a super zoom in this area is the type tv broadcasters use for things like golf matches. They cost a fortune and are good enough for TV resolution.

People assume optics have improved. Production techniques in real terms are the same as they have always been. Computers have been used for optical design for rather a long time. They just make the process easier. The main improvement in that area is the ability to predict where stray light goes. That has also been improved by better lens coatings but multi coating has also been around for a long time. I don't think the latest greatest in that area has reached camera lenses and maybe never will. It's usually called BBAR. Broad Band Anti Reflection.

The other thing that has been improved is glasses and cheap lens production techniques. New glasses make APO's more feasible but it's a term that is open to a lot of abuse. They also make the use of less glass feasible = lighter lenses than they used to be. Lense elements are often hot pressed rather than ground. There are reasons why these can't be precision optics which might explain why camera lenses generally only have a few aspherics in them. On the other hand maybe most are hot pressed as camera lenses fall short of being in the precision optics class. Lenses with lots of elements have problems in that area anyway as light waves are tiny and tolerances stack up.

I don't think things optical in a general sense can improve unless something completely new comes up which is unlikely. There are more accurate surface generating methods available - ionic machining but some how I doubt if that will reach camera lenses. In some respects I think lenses are worse than they were on occasion. As with early canon digital kit lenses they are sometimes designed in a rather limited way and priced accordingly. I'm not convinced price is a good indicator of quality though.

18-200mm lenses? People have said that they can produce acceptable large prints from lenses like that. Hardly surprising really. If a 100% view on a pc screen looks good as it's scrolled around in principle it could produce a print of that size that would look fine from circa 30in. The wonders of software. If it doesn't look fine at 100% it might do at 50% and that would still be a pretty big print on many cameras. Actually I suspect a 50% reduction may be needed in practice.Take it down to 1024x?? for a pc screen and many things would look fine even the output from a compact. Some may be able to see pixels on their screen from 10in? Barrel, pincushion, chromatic distortion etc can be removed with software to a certain extent so within limits that doesn't matter either.

John
Amateur optical designer stems from an interest in astro telescopes They are much cheaper on paper..
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[DanK]

I don't think the rule is hard and fast, and there are exceptions. The Canon EF-S 15-85 (zoom factor 5.67) is quite a good lens despite the large zoom range. It was my walk around lens until I went FF recently, and I was pleased with it. However, it does seem that most of the really excellent zooms are 3x or close. My approach has been to avoid anything much over 3x unless tests and reviews are consistently good. My only one now over 3x is a 24-105. I opted for convenience in choosing this over one of the various 24-70 lenses.

[ajohnw]

I don't think the rule is hard and fast, and there are exceptions. The Canon EF-S 15-85 (zoom factor 5.67) is quite a good lens despite the large zoom range. It was my walk around lens until I went FF recently, and I was pleased with it. However, it does seem that most of the really excellent zooms are 3x or close. My approach has been to avoid anything much over 3x unless tests and reviews are consistently good. My only one now over 3x is a 24-105. I opted for convenience in choosing this over one of the various 24-70 lenses.

That is a pretty well balanced zoom but to get a feel for what goes on at the long end look at these 2 reviews

http://www.photozone.de/canon-eos/46...3556is?start=1

http://www.photozone.de/canon-eos/42...18_50d?start=1

That zoom holds up well in the centre but not all of them do. Seeing the difference in practice depends on what is done with it.

The prime as usually sharpens up at around F5.6 and shows the usual other problems at wider apertures.

Where 3:1 comes in and probably less at the wide angle end is getting near prime performance or it may indicate a decent lens at it's price level.

John
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[jcuknz]

That x10 Angenuiex which Richard was talking about was available in the fifties. I didn't have one until some time later. Perhaps it is reasonably to say that the motion picture industry has led the way in this respect because of different requirements. It was difficult to crop movies so you shoot what you want.

[krispix]

My recollection of the 70-80's period is that Nikon offered one zoom lens. Maybe at some point in the 80's they may have introduced more It did sell too despite the cost.

Just checked my 1968 Nikon F Handbook. They made a f4.5 28 - 45mm, f3.5 43 - 86mm, f4.5 50 - 300mm, f4.5 80 - 200mm, f4-4.5 80 - 250mm (Discontinued about 1967), f8 180 - 600mm, f9.5-10.5 200-600mm (Discontinued about 1966), f9.5 200 - 600mm and f11 360 - 1200mm

As you can see none of them were particularly fast and all a bit weighty, the 360 - 1200mm came in at 6.6kgs (Nearly 15lbs). Imagine lugging that around all day!

I believe the 43 - 86mm was the most popular, but it wasn't really anything - too long for a wide angle and not long enough for a tele. Might have made a reasonable portrait lens but at f3.5 you would have been better off with the superb f1.8 85mm or the equally good f2.5 105mm.

[ajohnw]

Just checked my 1968 Nikon F Handbook. They made a f4.5 28 - 45mm, f3.5 43 - 86mm, f4.5 50 - 300mm, f4.5 80 - 200mm, f4-4.5 80 - 250mm (Discontinued about 1967), f8 180 - 600mm, f9.5-10.5 200-600mm (Discontinued about 1966), f9.5 200 - 600mm and f11 360 - 1200mm

As you can see none of them were particularly fast and all a bit weighty, the 360 - 1200mm came in at 6.6kgs (Nearly 15lbs). Imagine lugging that around all day!

I believe the 43 - 86mm was the most popular, but it wasn't really anything - too long for a wide angle and not long enough for a tele. Might have made a reasonable portrait lens but at f3.5 you would have been better off with the superb f1.8 85mm or the equally good f2.5 105mm.

I bought one of these around the date of your catalogue wonderful camera. Probably 69/70. Maybe I missed these as my main interest at that time was used Nikon lenses. I still have the manual and the leather extension and reversal ring bag about somewhere. The camera + lenses + rings and camera bag were stolen when our house was broke into about 24 years ago and never recovered. Along with my old passport with it's collection of European border crossing stamps. Not replaceable now. I did wonder about an F at times but became very happy with the nikormat. Never keen on the cost of having it serviced to get the shutter speeds checked and adjusted etc.

One curious thing is I came across the same camera bag 2nd hand in a shop in Wales about the time the 300D's came out and still use it for my Canon kit. Not the same one though. It must be 30-40+ years old and still fine. Probably still be ok in another 30 odd years.

http://www.mir.com.my/rb/photography...t/fseries/ftn/

John
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[RobertsMx]

I would add: expectations. We never see objective reviews of super zoom lenses.

[ajohnw]

I would add: expectations. We never see objective reviews of super zoom lenses.

They can be found eg

http://www.photozone.de/canon_eos_ff...8300_3556is_5d

Problem is though that sites like this one often disappear or change if they become too popular. The other problem is applying what tests like these mean in terms of actually taking photo's.

John
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[Colin Southern]

Least we forget -- the Canon EF28-300!

[RobertsMx]

Least we forget -- the Canon EF28-300!

I meant the really "super zoom" lenses, as in P&S cameras, or in video cameras as alluded to in the OP.

With likes of Canon 28-300 (or my own, Sigma 18-250), the performance obviously is much more compromise, especially in terms of distortion and softness at longer FLs.

[ajohnw]

I did have an interest in super zoom bridges and even bought one but it shortly went onto ebay. Bought due to a rather good price. The best review site I found was easily this one

http://www.photographyblog.com/reviews/

Not keen on their ISO noise test but at least there is something there and full images can be downloaded even raw if the camera can provide them.

They also look at some compacts. Stevesreviews can be useful but often not as much as it was - need to look at flaws in the photo's. Dpreview do reviews on wide variety of cameras but mostly dslr's. Other types tend to gloss over a lot..

The long end of many super zooms is often a bit sad as that's when max contrast is really needed. Looking at that link I posted though for the Canon EF28-300 it isn't that dramatically bad. People can probably find reviews there for some of the primes in that range too and compare.

As to what the numbers mean more difficult but if you compare the Panasonic 45-200mm at 150mm to the Olympus 40-150mm at 150mm I can assure you that the difference is noticeable even on reduced shots. Different approach to design too. Oly seem to like centre resolution and accept some fall off at the edge.

John
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