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UniSonBBS Aug 6, 2003 8:03 PM

Need some new guy help.. hehe
Hey everyone,

Ok. I am still debating on my camera right now. Either Nikon D100 or the Canon 10D. But I am looking at this lens for Canon "Canon 75-300 4-5.6 EF USM III Lens". I was wondering how you figure out the zoom on this thing? If I connect this to the Canon 10D is it the following zoom?

1.6x * 70-300mm = 480mm? / 35mm = 13.7x zoom

or is it

1.6x * 70-300mm = 480mm / 70mm = 6.8x zoom

Or is these math even right? Please let me know.
Such a newbie... :wink:


UniSonBBS Aug 6, 2003 8:11 PM

I hate repeating threads of something that was just talked about.... But what would you recommend for a lens. I really like to use zoom (Birds, bugs "That fly off if you get to close :P", and other things in the distance. But I want something that would beable to do some occasional portraits, etc. I guess to say, what would be good for an all around lens. But I would like to get a big zoom lens. My Olympus E-10 as you probably know is a 4x lens. And wish it could be a bigger zoom.


eric s Aug 6, 2003 10:08 PM

When thinking about a 35mm SLR (or DSLR) the "x" factor doesn't matter (mostly, see at the bottom.) What people care about is the actual mm, which you calculated correctly in both places.

If you want to compare the zoom to a pair of binoculars, then divide the max zoom by 50 (which is basically what the human eye sees.)

If you want to compare it to a consumer grade digital camera (for example a CoolPix 5700, Canon G5) then it is harder. The "x" factor like "4x" only describes the difference between the long end and the short end of a lens. It is a description of range. A 35-140 is a "4x" zoom. But so is a 100-400. So comparing the "x" factor in this way is basically meaningless. Gotta hate it when marketing people take something useful (the actual 35mm equivalent range of a zoom) and turn it into something near useless.

As to your other questions. I’ve heard reasonable things about the 75-300mm. I’ve never used it, as I have the 100-400L and 28-135 that overlap with that lens. I think that some others here have that lens, though. You might want to ask about it specifically… as in put it in the subject line, so it will catch attention.

The Olympus E-10 has a 35-140mm 35mm equivalent lens. That is not a very long zoom, but what it does have going for it is a very fast f2 fstop. So it should be fairly good in low light.

If someone made a good “all around zoom” then no other lenses would be made. (I’m exaggerating, but you get the idea.) Depending on your definition of “good”, it doesn’t exist. I have rather high standards, so for me it certainly doesn’t exist. In general, the longer the zoom the lower the quality. It is just the nature of physics/optics. Zooms have gotten better in the last 10 years, and for many people they are “good enough” but realize that a zoom with shorter coverage is easier to make than one with longer coverage.

We won’t get into the fact that almost everyone is subjected to cost constraints. So the statement isn’t “good”, but “good in my price range” (which you haven’t stated.)

I have heard good things about the Sigma 50-500. I’m surprised since it has a huge zoom range. If you could deal with the weight, size and cost, it might be the closest thing to a “good all around lens” for you. Most people just buy two lenses because then they will be lighter and you can leave one at home if you don’t need it.

Now that comment I made at the top should be qualified. I hinted at it above. To me, the only time the ”x” factor is useful is when it describes how long a range a zoom lens covers. All other things being basically equal, a 4x zoom will produce better quality pictures than a 6 or 7x zoom. The 4x will probably be smaller and lighter as well (but that is more an aspect of the highest zoom number and the fstop.) And I bet it is cheaper to buy two lenses that cover the same range then one large one (if they all produced the same quality pictures. If the longer zoom were inferior in some way, that is another matter.)


UniSonBBS Aug 6, 2003 10:32 PM

Thanks for the info.

Just to make sure I understand this correctly.
Lets say your 100-400mm lens is attached to your 10D.
That gives it 1.6x more correct? So at its full zoom it would be a 640mm zoom? Which in turn means the equivilent of what "x" zoom? Im sooo confused on figuring out the math beind this... lol

I appriciate your lenghty post of knollegde... :P


Frank Doorhof Aug 7, 2003 2:27 AM


The 4x 10x or 13x is not important anymore, that's the power of changable lenses.

Just concentrate on the mm's of the lens, 300mm is good, 400mm is beter :D.

Problem is on the wide-end, because the Canon multiplies everything with 1.6 a 28mm lens will be 44.8mm in real life.

For me that's no problem because I always use zooms, so the 10D is a life saver in costs of zoom lenses.


eric s Aug 7, 2003 8:27 AM

Frank Doorhof

I just thought I'd say that I agree completely with Frank Doorhof. My 100-400 rarely leaves my camera. I'd go for more reach (larger mm) if I could (but it costs too much... so I'll get it some day.) I take lots of pictures of birds and other wild animals. I'm never that close to them.

Why do you want to know the "x" factor? I agree with Frank, you don't need it... it doesn't really apply once you move to the realm of replaceable lenses. But clearly you want to know... so if we knew why maybe we can help you with other info instead.


JodyQ Aug 7, 2003 9:13 AM

10D - zoom
So you've decided to follow the E-10 to 10D crowd. Great!! I have the IS (Image Stabilization) version of the 75-300 lens. It is the one I chase my neighborhood birds with. The IS means, no Tripod (most of the time).

Anyway, since the 10D has a 1.6 multiplier, that makes the 75-300 lens have a 35mm equivalent range of 120mm - 480mm. Sort of like having a zoomable TCON 300 on the E-10. On the short side it is like the E-10 zoomed almost all the way out (without a TCON), and you can pick any length to just beyond the range of the E-10 with the TCON300).

This would be close to 3.4X to 13.6X zooming on a 35mm camera.

Now with the 50-500 Sigma (it is a heavy beast and a tripod is recommended -- no IS on it), with the 10D's 1.6 multiplier, you have a 80-800 equivelant zoom. That can pick up the mites on a blue-jays butt from the other side of a football field!!!!!! But so far I have only used it from my balcony to test that it works. I hope to get out with a tripod soon.

Here is a 75-300 shot I took from around 30 yards.

Hope this helps with the mathness of the question.


Lenses for 10D --- Canon 50 (F1.8 ) -- 28-135 IS (F3.5-5/6) -- 75-300 IS (F4-5.6), Sigma 15-30 (F3.5-4.5), and 50-500 (F4-6.3)

UniSonBBS Aug 7, 2003 5:03 PM


Thanks JodiQ!
That was fantastic! That clearly answers my question. I guess it just took someone that could step back a bit and see it from a new (Point and Shoot user) view... :lol:

Anyways, I believe I am going to get that Canon 70-300mm IS lens. You pay a bit extra, but I dont wanna have to set up a tripod everwhere I go. But should I get, say a 28-105mm lens also? I wanna beable to do some macro's here and there as well. But I think most of my photographs will mostly require a fairly large zoom or some zoom.

But I guess my over all question was. And I guess I should have made it alittle clearer.

Is this lens more powerful (As in zoom) then the Olympus E-10, and by how much? But I know the answer now. Its by a lot! :twisted: hehehe

UniSonBBS Aug 7, 2003 5:14 PM

What do people think about these lenses?

Canon EF 28-135mm f/3.5-5.6 IS USM = 216mm Eq. right?
Canon EF 75-300mm Zoom f/4.5-5.6 IS USM Lens = 480mm?

Should I get both? Or which do you enjoy the most?

Also what about dust and stuff getting on my censer? Should I be concerned with that during len changing? And if it seems to have dust, what do I do about it?

JodyQ Aug 7, 2003 6:28 PM

28-135 (And 50 MKII 1.8)
Those of us who aren't rich, really like both those lenses you list. The well-to-do would say only the "L" lenses are worth purchasing. And if I had the $$$$$.$$ I would too.

The 28-135 is what I normally walk around with when I am not bird hunting. It is what I frequently use when I following golf students on the course. (I am allowed to get closer than most).

For example, I was using the short end (the 28mm side of it) on this shot, and I was still unable to get the top of the swing.

These 2 sequences (untouched except turned into small animated gifs) were also shot with the 28-135. (go to the page)
Notice that I "stopped" the ball... That is one of the reasons I left the E-10.

I am not a macro fiend so I can't say much on which lenses do that well, other than both of these zooms allow you to get a pretty darn close look at your subject, but I gather the lenses that are made for it, are much, much, better.

The other lens I would definately get is the cheapest of them all. For around $70 (less or more) you can pick of the 50mm (Normal EF 50mm f/1.8 II Autofocus Lens). Yes, it is inexpensive, but it is quite good to use indoors for the "normal" point and shoot events in our lives.

Now I'll finish this post, and go back and see what questions I might have missed.


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