Started thinking about the need for more length, but not necessarily girth!

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Originally Posted by Donald

I think the key difference between cropping severely on a 200m shot and a genuine 400mm shot is the perpsective achieved. A tightly cropped 200mm shot is still going to look like a 200mm shot, whereas the 400mm shot is going to produce a very different relationship between foreground and background objects (or that's what I'm telling myself).

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Nope :)

You're kidding yourself I'm afraid, perspective only changes with moving relative positions of camera and subject.
From the same place, of the same subject, a crop and a zoom will look exactly the same (excepting IQ issues if you crop too far)

Try it at 200mm and 100mm cropped ;)

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Originally Posted by Dave Humphries

Nope :)

You're kidding yourself I'm afraid, ...

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Stop being right - You're bursting my bubble.

Thanks Dave - I don't know why I got myself onto that particular line of thinking. Have now properly informed myself by reading some more.

Anyway - I have had clearance from the Chief Financial Adviser (the equivalent of Rob's 'head gardener') to move to purchase.

Choice number 1 would have been to sell the 70-200 f4 L IS and replace it with the new generation f2.8 + a 2x converter. But the treasury official (in the room next door) persuaded me (the bruising is healing) that this was not a realistic option.

So, I am now heading towards the Sigma 120-400mm f4.5-5.6 DG OS HSM. With the obligatory (I believe, though not everyone agrees) Hoya 77mm Pro1 UV Filter and a Manfrotto plate to attach to the tripod holder for quick release I'm just under £800 from Warehouse Express.

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Originally Posted by Dave Humphries

perspective only changes with moving relative positions of camera and subject.

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Or put another way, WA lenses don't cause perspective distortion -- they simply allow you get closer ... and it's the "getting closer" that causes the distortion.

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Originally Posted by Donald

Stop being right - You're bursting my bubble.

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Sorry mate :o

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Originally Posted by Donald

Thanks Dave - I don't know why I got myself onto that particular line of thinking. Have now properly informed myself by reading some more.

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It happens from time to time, I trust you'll do the same for me one day (no, really I do)

In fact there was something I got wrong here not so long ago and someone put me right, but it's OK, I have mentally erased it from my mind in order to maintain a self-illusion I know what I'm talking about :rolleyes:

Cheers,

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Originally Posted by Dave Humphries

Nope :)

You're kidding yourself I'm afraid, perspective only changes with moving relative positions of camera and subject.

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Whilst accepting Dave's correction as above, I continued to trawl looking for more on this subject and, in particular, to gain some understanding as to whether there was a common vocabularly/terminology, as it seemed that poepel were callign the same thing by different names.

As I trawled, I came across this 2006 posting in a discussion forum by someone called Doug Kerr from Texas. So that we properly reference our sources, this is it.

"Returning to "distance compression", I have often pointed out that this effect is not, as commonly said, a creature of large focal length but rather only of the distance from the camera to the group of objects (noting that we often of course use a large focal length in such a situation to allow us to appropriately fill the frame with our "composition")

But I now realize that this is in fact not the whole story.

Indeed, the geometric relationships we characterize as "distance compression" result only from the subject distance, not to focal length. But those geometric relationships only look "unnatural" to us when we observe the object group, in the viewed image, at a significantly-greater angular size than they would have subtended if we had viewed the scene from the camera (just as discussed above).

Now, assuming a certain common range of "camera-to-print" magnification, M, and a certain common range of viewing distance, d, the image compression effect, as perceived by the viewer of the print, will in fact be greater for greater values of focal length.

We can express this criterion algebraically, using the same notation as above, as:

f>>d/M

So I now see that I need to be more cautious in wagging my finger at those who speak of distance compression as being produced by large focal length."

Now, as I wrote elsewhere recently, maths and me just never did get on. So I don't claim to get the detail of all that he writes.

Donald, you already have a 70-200. A 300 f/4L IS would compliment it nicely. Add a TC and you will be covered from 70-420. You've seen what the 300 if capable of, and there is almost no loss of iq with the 1.4TC. What are you waiting for, go get one.:)

Donald...

I know you like to use a tripod for a lot of your shooting. I just learned that the 70-300mm f/4-5.6L lens doesn't come with a tripod ring and apparently the inexpensive rings sold on eBay do not fit. So, if you want a tripod ring equipped lens, you are forced to purchase the expensive Canon OEM model.

http://photography-on-the.net/forum/....php?t=1069820

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Originally Posted by Steve S

Donald, you already have a 70-200. A 300 f/4L IS would compliment it nicely. Add a TC and you will be covered from 70-420. You've seen what the 300 if capable of, and there is almost no loss of iq with the 1.4TC. What are you waiting for, go get one.:)

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Thanks, Steve

Unfortunately, by the time you add in the tripod collar and the 1.4 extender, it pushes just too far out of my comfort zone so far as price is concerned. I would've loved an L lens at this sort of length, but I have to be realistic, particularly given that our house in in chaos at the moment as we get a wood burning stove installed and the guy has already been out to start pricing the cost of replacement windows upstairs.

So, there are competing priorities (so I'm told!). In fact, I've been told that there are no competing priorities at all. I ain't getting a long L and that's that!

Okay. The deed is done.

Thank you all for your extremely constructive and helpful suggestions and ideas. They really were.

I've ordered a Sigma 120-400mm f4.5-5.6 DG OS HSM.

It's not top of the tree, but comments by those who use are very positive. We all have to compromise (unless we rich enough that we don't have to).

I hope that by this time next week, I shall be able to comment on first impressions.

Thank you again for holding my hand through this decision-making process.

Oh, this is too exciting! I'm really happy for you, Donald because, I'm pretty sure that you'll enjoy it (even if it isn't the very top of the line)!!! Too bad Rob has headed to the northern Welsh mountains, again, he always is the one to remind us that it's not the gear....;)

and, I just want you to know that a puppy helped me type this post. Apparently it's really good to lick the keyboard - bet you didn't know that - I'm sure I didn't.:p

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Originally Posted by Katy Noelle

and, I just want you to know that a puppy helped me type this post. Apparently it's really good to lick the keyboard - bet you didn't know that - I'm sure I didn't.:p

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Could you send it over here. My keyboard is filthy and need a good lick.

Right. It's just arrived - the Sigma 120-400mm f4.5-5.6 DG OS HSM.

First impressions?

• The autozoom is fast and accurate
• It feels very solid - there is no lens creep. In fact the zoom ring is quite firm and requires more than just a casual twist.
• Took shots of a tiled roof as a means of evaluating the softness that all reports state is present when wide-open (f5.6) at 400mm. I'm quite content with what I'm seeing.

So, it's a case of so far so good!

Oh, goody, goody! Oh, boy! Can't wait to see what comes of it all!:)

Richard:
I bought the EF70-300 f/4-5.6L IS USM lens. I am very annoyed with Canon that it didn't come with a tripod ring. However, that said, it works fine on my 7D with a Manfrotto 496RC2 ball head with no droop. The 496RC2 is not a very heavy ball head but I've done a number of tripod shoots without problems, both horizontally and vertically. Together the two are well-balanced and have been excellent hand held shooting birds in flight. Even with the 480mm equivalent reach on the 7D though, I will need more reach for my surfing and wildlife photos.

Canon 100-400 L IS has minimum focus of 1.8 m (6 feet), so you may still get your photo of the butterfly, if it doesn't fly away!

I just sold my motorcycle which gives me the green light from the wife for a new L lens. Im thinking of getting the new 70-300 L as a replacement for the 55-250 that got stolen. I want lens that i can reach past 200 with and still hike with it around my neck for a few hours. My thought is the 70-200 and teleconverter would crush my neck after a few miles.

Paul:
The EF70-300 f/4-5.6L IS USM (2.32 lbs) is not as heavy as the EF70-200mm f/2.8L IS II USM (3.29 lbs). But, it's not a lightweight either. I have used the EF70-200mm f/2.8L IS II USM as well and it feels considerably heavier (great lens but short on reach for my purposes).

With 7D and EF 70-300, the set-up weighs 4.22 lbs. I made that load easier with a Tamrac Neoprene Boomerang Digital Camera Strap - Black N505701 ($30). The strap makes the load quite easy to bear, whether across the shoulder or around one's neck. I also got a neoprene strap for my tripod/ballhead set-up so I can walk quite a while with no strain. Haven't tried any serious backpacking with that rig though.

I also have a 7D and was thinking along similar lines. 70-200 seems a little short and a bit heavier and would be even worse with an extender. The only drawback as far as i can see is that i dont believe the extender works with the 70-300. I would love if the updated the 100-400 and somehow shaved about a half pound from it.

You're right. The EF70-300 f/4-5.6L IS USM does not work with an extender. But, on a 7D it's the equivalent of a 480mm.

I'm taking a EF100-400 f/4-5.6L IS on a photo trip to Yellowstone/Tetons next month. That will influence my next buy. I may wait for the follow-on to the 100-400 or look at a 500 prime.