Big Test

When we say Big Test, we mean Mam­moth Test, with our re­view of eight su­per-sized telephoto zoom lenses

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For­get all that ‘less is more’ bunkum. Take a step up from a bud­get 55-200mm or 70-300mm telephoto zoom lens and you can lit­er­ally hit the big time.

One op­tion is to stick with a mod­est max­i­mum fo­cal length but to go for a faster aper­ture. One of the Sigma lenses in this group test is unique in com­bin­ing a 120-300mm zoom range with a wide f/2.8 aper­ture that re­mains con­stant through­out its zoom range. It’s like shift­ing up a gear from a stan­dard 70-200mm f/2.8 lens, grab­bing ex­tra reach with­out los­ing an f/stop. That’s great news for keep­ing shut­ter speeds fast in dull light­ing, and for min­imis­ing depth of field.

An­other op­tion, which we cov­ered back in is­sue 29, is to buy a good-qual­ity 70-200mm f/2.8 lens and sup­ple­ment it with a 1.4x or 2x tele­con­verter. This gives you a max­i­mum fo­cal length of 280mm or 400mm re­spec­tively, with a drop in widest avail­able aper­ture to f/4 or f/5.6. This time, how­ever, we’re con­cen­trat­ing on big lenses that do the job on their own.

The Sigma 120-300mm is ex­tra­hefty, thanks to its com­bi­na­tion of 300mm fo­cal length and wide f/2.8 aper­ture, and while the other lenses on test are also bulky – in or­der to ac­com­mo­date that ex­tra-long, su­per-telephoto reach – they are smaller and lighter than the Sigma. This is be­cause the nar­rower widest aper­ture en­ables the front el­e­ment, and there­fore the over­all di­am­e­ter of the lens, to be smaller. This is true of most of the vari­able-aper­ture lenses on test, which gen­er­ally start off at f/5 at the short end of the zoom range, and shrink to f/5.6 or f/6.3 at the long­est end.

The max­i­mum fo­cal length of most lenses in this test group is be­tween 400mm and 600mm. The zoom range is more gen­er­ous in some cases than oth­ers, rang­ing from two times in the Nikon 200400mm lens to 10 times in the Sigma 50-500mm. To give ex­tra reach, new con­tenders in­clude the Sigma and Tam­ron 150-600mm lenses. Go­ing fur­ther still, the gi­gan­tic Sigma 300-800mm gives class-lead­ing telephoto reach, but mea­sures more than half a me­tre long and weighs nearly 6kg! By con­trast, the Nikon 80-400mm and Sigma 150-500mm lenses are rel­a­tive lightweights, at just 1.57kg and 1.78kg re­spec­tively.

Typ­i­cally, con­stant-aper­ture telephoto zooms re­tain a fixed phys­i­cal length. With vari­ableaper­ture de­signs, the over­all length of the lens can nearly dou­ble when you zoom from the short­est to the long­est fo­cal length. What looks like a man­age­able propo­si­tion in the box can quickly trom­bone into some­thing un­wieldy. Th­ese lenses typ­i­cally also have an ex­pan­sive girth; some have over­sized fil­ter/ ac­ces­sory at­tach­ment threads of 95mm or even 105mm, mak­ing fil­ters very costly. Oth­ers have no op­tion for front-mounted fil­ters at all, in­stead of­fer­ing the fa­cil­ity for ‘drop-in’ fil­ters of 46mm or 52mm in di­am­e­ter, mounted near the rear of the lens (see com­par­i­son ta­ble, page 108, for de­tails).

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