# A 500mm f/5.6?



## Albi86 (Feb 21, 2014)

I recently got my Tamron 150-600mm and I'm loving it. Tamron has shown that it is possible to build a pretty decent 150-600mm f/6.3 zoom at an affordable price. This has some interesting implications.

It is often thought that with long and fast lenses, the amount of glass needed is a big factor in the price hike. If I am correct, a 600mm f/6.3 must have a front element with a diameter of at least 95.24mm. The Tamron is just about there, with a 95mm _filter thread_. This could explain how sharpness grows considerably when stopping down to f/8, as if the size of the front element was barely enough to achieve the FL/aperture combination desired. 

I would like to share an observation. A 500mm f/5.6 would have a front element with a diameter of at least 89.28mm. This makes the use of a 95mm filter thread much more advantageous. In other words, it should be possible to build a 500/5.6 with more or less the same glass as for a 600/6.3 - thus around the same price. If you consider that building a shorter prime should be easier than building a longer zoom, a 500/5.6 at around 1100 EUR/USD is both technically feasible and promising IQ-wise. The Big Ron (or Tamrosaurus, or Tankron) gets really sharp at f/8; trading 100mm of focal length for a full stop of light (without losing IQ) could be worthwhile in many situations. For reference, the Canon 400/5.6 L takes 77mm filters having a front element of at least 71.43mm and the IQ is still good although it's an old lens. 

Thoughts?


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## Lightmaster (Feb 21, 2014)

well there is a similiar thread about a 600mm f5.6 or f6.3.

http://www.canonrumors.com/forum/index.php?topic=19476.0

the mods my want to join this as it´s basically touching the same issues.


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## Albi86 (Feb 21, 2014)

Lightmaster said:


> well there is a similiar thread about a 600mm f5.6 or f6.3.
> 
> http://www.canonrumors.com/forum/index.php?topic=19476.0
> 
> the mods my want to join this as it´s basically touching the same issues.



The other thread is about the wish for an affordable 600mm f/5.6.

Here I'm comparing a 500/5.6 prime VS a 600/6.3 zoom, since the glass involved should be similar and the latter does actually exist.


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## Lightmaster (Feb 21, 2014)

Albi86 said:


> Lightmaster said:
> 
> 
> > well there is a similiar thread about a 600mm f5.6 or f6.3.
> ...



still it´s basically touching the same issues.
no need to repeat the same arguments here i guess.


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## fussy III (Feb 21, 2014)

I am hoping for this lens (500/5.6) for so long now. To me it is all about weight and "croppability". I want to be able to use a 500/5.6 like a zoom by simply cropping it to 800mm or even 1000mm on a 24 Megapixel+ camera-body. Cropping in post allows for loose framing. Much better for action and wildlife than zooming in to tight while the action is happening. But it takes a quality prime to do that! 

Currently I am following this cropping strategy by carrying a 500/4.0 on a 5D Mark II. In addition, I take a 70D with a 55-250 STM, a 24-105 and a 10-22. To me, that is the best compromise. Lowers weight but retains image quality plus it is redundant to some extend. If rthe 70D lets me down, I still have the 24-105 and the 500mm prime for example. At the same time, I do not need to carry a 17-40 L or a 70-200 L because these are the focal lengths that I do not prioritize on.

To me, this combination of 55-250 and 500 L is much better than a 150-600 Zoom that I cannot crop or use with a Konverter because image quality is going down on the long end. Ideally, I would carry a 500/5.6 IS instead. 

To give a comparison here two different sets of equipment:

Combination A
The weight of 55-250 STM and 500/5.6 L IS plus 70D and 5D II would amount to appr. 4kg. Effective usable Zoomrange by cropping would be lets say 88-800mm with a gap between 400 and 500 mm. But the effective 400mm of the STM can be cropped to 500mm on the 70D with ok results. 500mm from an L prime wide open on a 70D will give excellent results. Same would be true when croppen to APS-C size from a FF-sensor.

Combination B
The weight of Tamron 150-600 on a 5D III is 2,9 kg, with a redundant 5D III it would be 3,85 kg. Cropping from 600 mm is hardly possible, even 500mm stopped down to f8 on a 70D is not really nice.

I much prefer the additional zoomrange and reliabilty of Combination A over Combination B.

Conclusion: Please build a 500/5.6 L IS USM, Canon, and make it as sharp as possible (no DO please).


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## Lightmaster (Feb 21, 2014)

people will argue that making a really good 500mm f5.6, that has a place in the market, will need tighter tollerances (to make it optical superior) and therefore make it much more expensive then existing zooms. 

not only the amount of material needed is the problem but also the amount of work you have to put in it, to make such a prime worthwhile.

i guess there is a reason nobody has done such a lens yet.

again.. to me it looks like the same arguments as in the other thread apply.

thats said, i too would like to have a very sharp 600mm f6.3 or 500mm f5.6 for around 2500 euro.


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## Plainsman (Feb 21, 2014)

From the photographers point of view it would be entirely logical and very nice for someone to make a 500/5.6 IS II. A high quality one for slightly less than a 300/2.8 IS II would be a big seller.

But it won't happen from Can/Nik because it would impinge seriously on sales of the big whites/blacks further up the price chain.

Canon are not here to please the whims of photographers. They are here to maximise profits for shareholders.

I think future trends will be towards high quality zooms like the 70-200/2.8 and the 200-400/4. Perhaps a few more of these and Canon could delete primes completely from their range.

The best non Can/Nik 500 prime out there still in production is the old Sigma 500/4.5 DG but maybe the new Tamron can beat it for sharpness at 500? A side by side test would be interesting.


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## Albi86 (Feb 21, 2014)

Guys, there's one point that maybe I didn't explain all too well. My observation is not about the feasibility of a 500/5.6 or a 600/6.3 for 2500€. It's about the feasibility of such a lens _at the same price_ of the current Tamron 150-600. 

The overall hypothesis is that if a 600/6.3 is viable, then a 500/5.6 should be too. *It's not a wishlist thread*, I would like to discuss the technical implications of that. Comments on that?

Designing and building a 500mm prime is arguably easier than a 4x-600mm zoom, so that should offer the basis for better optics. Comments on that?


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## fussy III (Feb 21, 2014)

Dear Plainsman and albi,

Personally, I wouldn't care about the price too much if it is a good lens. If Tamron makes it good AND cheap, that is fine. If Canon makes it excellent and expensive, even better. 

I do not believe that such a lens made by Canon would mean less profit to the company. On the contrary. Many people, e.g. birders, so far are investing in Zoom-lenses like the Tamron 150-600 not because they are cheaper or because they want a zoom but because they cannot carry a heavy Supertele in addition to binos and telescopes.

At the same time, these customers are complaining about resolution of their Zooms at the long end. Give them a 500/5.6 and they will buy it, even if it cost 3.000 Dollar. When needed, they could tweak it into a nice telescope or have it on a sniper-belt as a Photo-ID-tool at all times.

Personally, as a nature photographer, I would want to have it as an addition to my 500/4.0, not as a substitute. 

Whoever builts a 500/5.6 first will open a new niche, not close an existing one.


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## Random Orbits (Feb 21, 2014)

Albi86 said:


> Guys, there's one point that maybe I didn't explain all too well. My observation is not about the feasibility of a 500/5.6 or a 600/6.3 for 2500€. It's about the feasibility of such a lens _at the same price_ of the current Tamron 150-600.
> 
> The overall hypothesis is that if a 600/6.3 is viable, then a 500/5.6 should be too. *It's not a wishlist thread*, I would like to discuss the technical implications of that. Comments on that?
> 
> Designing and building a 500mm prime is arguably easier than a 4x-600mm zoom, so that should offer the basis for better optics. Comments on that?



If Tamron built a 500/5.6, it might be more expensive/heavier than the current 150-600. According to Dustin Abbott, the Tamron is at f/6.3 starting at 411mm. If it were at f/5.6 at 500mm, then you might have been onto something...


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## Albi86 (Feb 21, 2014)

Random Orbits said:


> Albi86 said:
> 
> 
> > Guys, there's one point that maybe I didn't explain all too well. My observation is not about the feasibility of a 500/5.6 or a 600/6.3 for 2500€. It's about the feasibility of such a lens _at the same price_ of the current Tamron 150-600.
> ...



Good point, but I'm not sure if the logic translates 1:1 from zooms to primes. In other words, I don't know if/how the zooming mechanism has a role in that.


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## Hannes (Feb 21, 2014)

I would think it would more likely be a DO lens if canon made one as hat would really bring down weight. Hopefully the can sort IQ out


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## StudentOfLight (Feb 21, 2014)

Hannes said:


> I would think it would more likely be a DO lens if canon made one as hat would really bring down weight. Hopefully the can sort IQ out



DO would bring down weight but drive up cost.


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