Future fast long teles. Is there a limit to there usefulness?

[alan_woolnough]

Hello All,

 

As an owner of a last generation 500mm f4.5, whose main interest is

in bird photography and am unlikely to ever be able to afford a top

of the range, latest model super tele, i am very interested in the

latest developments and trends. I was prompted to write this, after

reading a posting on the unarchived forum regarding a possible? 500

f2.8

 

As long lenses get faster, and therefore bigger, it appears that the

weight can be offset slightly by using lighter modern materials.

However, when used wide open, the depth of field is very narrow. This

is often considered to be an advantage with bird photography, but im

starting to wonder if there will come a point when a lens will become

too fast, regarding d.o.f.

 

I realise that the lens can always be stopped down, but if the aim is

to use an ultra fast lens for higher shutter speeds or slower film or

lower light shooting, then in some cases this defeats the object.

 

Even at my lenses f4.5, i can sometimes struggle to get certain birds

entirely within the d.o.f. if im lucky to get very close.

 

I guess there will always be someone whose circumstances would allow

the use of a 600 f1.4 if they could afford one {assuming the trend

continues}, but for someone in my situation, i think that f4.5 or f4

for a 500/600 is about ideal max aperture for me, here in the UK.

 

As a member of the older generation, my views are probably well out

of date, and im pretty clueless about digital gear, so i would be

interested in others views as to whether there will come a time when

lenses become so fast that actually become a disadvantage for general

bird photography {regarding d.o.f}, especially as the prices of these

future lenses will be beyond my imagination.

 

All the best

[steve_dunn2]

<p>Dunno what system you're using, but at least in the Canon world, the choice of speeds at various focal lengths doesn't seem to be shrinking. At 300, you can pick 2.8 or 4; at 400, you can pick 2.8, 4 (though it's ridiculously expensive), or 5.6; at 500 and 600, you only get one choice, but AFAIK it's always been that way, and if you want a slower 500 or 600, you buy a shorter lens and a TC.</p>

 

<p>I guess the thinking is that the market for 500 or 600 (or 800 or whatever) lenses is primarily for pros who want shallow DOF most of the time - this is the norm for things like sports and nature photography - so perhaps they don't think there's much of a market for a slow supertele? Just a guess. Or maybe since you can only go one stop slower (the 500 and 600 are f/4, and you lose AF on most Canon bodies if your lens is slower than f/5.6) they don't feel the size and cost savings would be worth it - at 300, you get a lens 1 stop slower than the big glass because that makes it a reasonably small, light, and inexpensive lens, but a 600/5.6 is still a fairly substantial piece of equipment.</p>

[thidglance]

DOF isn't the issue - try out this site.

 

http://www.eddiebonfigli.com/dof-calculator.html

 

 

You can try different focal lenghts and get a whole table of DOFs at different F stops and focusing distances. The reason people use the big super telephoto lenses is bight viewing and faster shutter speeds. Also quality - if you have a good F5.6 lens and a good F4 lens shot at F5.6 the F4 les is likley going to be sharper.

[alan_woolnough]

Thanks Steve/James

 

I probably didnt make my posting clear {a common problem fo me}, Im not looking for a slower 500mm lens. I tend to use mine wide open at 4.5 most of the time, and very occasionally depth of field can be a problem with certain birds at certain distances so a faster 500mm lens would increase the problem in this particular situation unless it was stopped down. Admitedly it would probably increase its sharpness, but at the sizes that i enlarge to, i wouldnt be able to justify spending a small fortune as im extremely satisfied with the results from my present lens.

 

Im really just wondering if the time will come when lens manufacturers decide that they have gone as far as they can with wide apertures, because of the decreased d.o.f when used wide open, compared with todays modern fast teles. Im mainly talking about bird photography here.

 

Thanks again

[bobatkins]

The main problems with longer, faster lenses is size and weight. They both go up by some non linear function. A 300/2.8 costs maybe 3 or 4 times more than a 300/ and weight goes up by a factor of 2. A 400/2.8 costs maybe 4 or 5 times more than a 400/5.6 and weight goes up by a factor of 4.

 

Nikon once made a 300/2.0 lens. It was huge, heavy and obscenely expensive.

 

So if there was a 600/1.4L IS, you couldn't afford it and you probably couldn't lift it. The front element would be at least 17" in diameter and wide open performance would probably suck.

 

Given the less than enthusiastic acceptance and high cost of the 400/4 DO lens, even if a 500/2.8 DO was introduced (it would have at least a 7" front element, larger than a 600/4 or 800/5.6) I don't think it would be practical for 99% of telephoto shooters.

 

I think there are good, practical reasons why you don't see lenses faster than f4 at 500 and 600mm. A 500/2.8 would be a great "showcase" lens, like the 1200/5.6L. Know anyone who carries one of those around?

[alan_woolnough]

Thanks Bob,

 

I did wander into the realms of fantasy with my 600 f1.4 remark, but ive been wondering where tele speed will end. It appears that most users of long teles find that 600 f4, 500 f4.5 and 300 2.8 is about as fast as they require for the vast majority of their stuff in their circumstances. Im certainly happy with 4,5 for my 500mm. I makes me wonder why manufacturers are contemplating faster max apertures {If there is any truth in it}. I guess there will always be a market for specialised lenses, but i would have thought there wouldnt be much need to go much faster than whats available today. {but what do i know}

 

Cheers

[brian_kennedy]

Alan, I doubt Canon is contemplating larger apertures for the superteles except maybe as a "showcase" lens, as Bob suggests (50/1.0 and 1200/5.6 lenses -- and I'd put the 400/4 DO in that category, too). A 500/2.8 DO does not sound attractive to me, a nature photographer. Maybe it would be attractive for sports shooters.

<P>

But if your wondering only about depth of field, try one of the online <A HREF="http://www.google.com/search?as_q=depth+of+field+calculator&num=10&hl=en&ie=UTF-8&oe=UTF-8&btnG=Google+Search&as_epq=&as_oq=&as_eq=&lr=&as_ft=i&as_filetype=&as_qdr=all&as_occt=any&as_dt=i&as_sitesearch=&safe=images">DOF calculators</A> sometime (link goes to a Google search -- <A HREF="http://www.reflectiveimages.com/depthoffield.htm">here</A> is one such calculator). Try plugging in some numbers there.

<P>

According to the calculator above, focused at 50', a 500/4.5 has 9.54" of DOF wide open; a 500/2.8 would have 5.94" of DOF wide open. At 25' with 500mm, DOF is 2.31" at f/4.5, 1.43" at f/2.8. Decide for yourself if that's much of a difference.

[bobatkins]

Manufacturers will always push faster lenses because it gives them a marketing edge. Canon had a 500/4.5, then Nikon had a 500/4, then Canon produced a 500/4. I suppose someone might make a 500/3.5 or even a 500/2.8 just to get "one up" on their competitor, and no doubt a few photographers would buy one for much the same reason!

[richard_cochran]

To a pretty close approximation, DoF is determined by

magnification and aperture. In other words, if you can fill

the frame with a certain sized bird at f4, your DoF will

be very nearly identical whether you use a 50mm or 1000mm

lens to do it. The DoF you lose by going to the long

lens is gained back by the longer distance, or vice versa.

<p>

The longer lens WILL blur the background deeper at the same

aperture. You can think of this as a consequence of the

fact that the longer lens magnifies the background more,

and more magnification means less DoF.

<p>

If you can get adequate DoF to take a frame-filling

photo of an egret at f4, it's probably easier to get

into position to do that with a 1000mm f4 lens than a

200mm f4. The 200mm f4 would be a lot cheaper,

lighter, and less prone to camera shake and

atmospheric turbulence, though. But the 1000mm lens

doesn't have a significant DoF disadvantage.

<p>

Example: a 200mm f4 lens focused at 20 feet gives

8.486 inches of DoF, while a 1000mm f4 at 100 feet

gives 8.484 inches, both according to <a href="http://www.reflectiveimages.com/depthoffield.htm">

the DoF calculator referenced in an above post</a>.

Either will fill the frame with a subject 3.685 feet

high, according to <a href="/making-photographs/lens">

the "learn" section of Photo.net</a>. While keeping

the same subject size, a fivefold

change in focal length caused less than 2

thousandths of an inch change in DoF, for all practical

purposes, identical.

[derek_franks2]

My concern about the future of fast long telephoto lenses heads down a different track. My D100 has a 1.5x multiplication factor (I'm sure somebody is going to say that this isn't technically correct, but it's basically the same end result). This makes my 300f4 a 450f4. With a 1.4 tc, I've got a 620f5.6.

 

Obviously, Canon is moving towards full frame DSLR sensors. However, Nikon seems to be indicating that they're sticking with the smaller sensors that result in the magnification factor. We'll know more after the dust settles from photokina (sp?) next month, but it seems like an awful waste of money and glass to stick a 600f4 designed for a 35mm frame size on a digital camera that will only be using part of the glass.

 

Don't get me wrong, I love my D100 but I won't be buying any glass bigger than my 300f4 until I have a better idea of where the DSLR market is heading.

[bobatkins]

Don't worry Derek, Nikon will eventually catch up with Canon, Contax and Kodak and make full frame sensors for their DSLRs. If they don't they'll be doomed to be "second tier" DSLR suppliers.

 

Don't forget a 600/4 needs a 6" front element, whether it covers 35mm or APS and a 300/4 needs a 3" front element. The front elements are where most of the cost is in these lenses. They aren't likely to get any shorter either. I can't see telephoto lenses designed for smaller sensor cameras being significantly shorter, lighter or cheaper than full frame lenses. Of course if you make the sensor small enough and give yourself a 5x multiplication factor you can have a "500mm equivalent" lens the size of a 35mm 100mm lens, but that's not what you're talking about with DSLRs

[awahlster]

Canon made a real nice 400mm f2.8 in the FD mount I've used one a bit on the heavy side for handheld work but on a good pod very bright and easy to focus. I know everything now days has to be new and better every two years but I have 30 canon FD mount lenses and 9 bodies and I don't have the cost of the latest Digital body and a 600mm f4 Is in all of it. So while some wonder what is the best lens to get to try to do everything I just wonder what body to get for the next lens I'm ogin to buy. oh I have from 20mm to 600mm along with zooms from 24mm to 200m Bodies: F-1N, 2)T-90's, 2)A-1's, 2)AE-1P's, AE-1, FTB. I can do anything from 4-1 macro to 1200mm f9 Kind of fun to buy about 20 years behind the curve. And I'll put my Crowned Sparrow shots or my toadstools up against anyones. My next lens is going to be a 500mm f4.5L whole kit including a 1.4X-A in EX+ condition is only going to cost me $1500.00 from a local dealer. Beat that with AF anything!!!<div></div>

[alan_woolnough]

Thanks all, for replying,

 

I have very little experience in different varieties of situations, as most of my time doing bird photography has been from my hide. As my 500 lens has been my main lens for many years, ive tended to only use it at the 5 meter to 7 meter distances as this has been the most suitable distance for the birds i tend to photograph, in order to get a reasonably good sized image without a tc. Ive found that im often on the limit regarding d.o.f. in that situation. As i usually only photograph from those distances, flash is an option that i have used sometimes, preferably as fill, but as i said on my posting i have last generation gear, and the slow sync speed can give me other problems. Bearing in mind the limitations of my gear, i have gradually over the years narrowed down my shooting options to get the best final result i can with the stuff i use in the situations i find myself in. I rarely shoot finch sized birds, or birds in flight because of this, however, i enjoy my limited approach to bird photography even though its been "forced on to me" by the cost of modern auto focus IS lenses, and my stalking skills are not great. Im entirely satisfied with my equipment used in the way i do, and ive found 4.5 to be the limit for my situation which prompted my posting.

 

Thanks everyone for their views.

[craig l]

Off the topic, but. . .Mark, please take this as intended, a gentle correction, your shot is of a White Crowned Sparrow (not black, although that seems to be an equally accurate description. . .)

[mats nilson photography]

A little late, but never the less (oh well, maybe somewhat less...). 1) I believe an increased maximum aperture may allow faster and more accurate AF-focusing, since there is more light and "defocus" to work with and 2) as far as I know, a 300/2.8 at f/4 and a 300/4 at f/4 do not produce quite identical results, I much prefer the out of focus areas of pictures taken with the 300/2.8 at f/4.

[alan_woolnough]

Thank for that Mats,

 

You make a good point, and one that should have occured to me. Tc use did not cross my mind as ive never used them {although ive recently purchased a 1.4 to try out}

 

Thanks again

[alan_woolnough]

Sorry Mats,

 

You didnt mention TCs, but your points make sense.

 

Either my eyesight is going, or im losing my mind.

 

Thanks