TAM­RON SP 24-70MM F2.8 DI VC USD G2

Fol­low­ing the 70-200mm model, Tam­ron gives its SP se­ries 24-70mm f2.8 the G2 up­grade to give both Canon and Nikon D-SLR users a highly com­pet­i­tive al­ter­na­tive.

Camera - - NEWS - PAUL BUR­ROWS RE­PORT BY

Tam­ron’s re­vival con­tin­ues with its lat­est ‘Gen­er­a­tion 2’ up­grade of an SP se­ries lens, this time the 24-70mm f2.8 zoom which, like its 70200mm f2.8 sta­ble­mate, presents a cred­itable al­ter­na­tive to the cam­era brand mod­els.

They must be putting some­thing in the wa­ter over at Tam­ron at the mo­ment. After a long pe­riod when great ri­val Sigma was mak­ing all the run­ning, it’s now hard to keep up with the steady stream of new lenses from Tam­ron – both fresh de­signs such as the 18-400mm su­per­zoom for ‘APS-C’ sen­sors, and the on-go­ing ‘Gen­er­a­tion 2’ pro­gram of up­grades mod­els.

We’ve al­ready seen the G2 ver­sion of the SP se­ries 70-200mm f2.8 tele­zoom – which com­pared very favourably with Nikon’s third-gen ver­sion of its AF-S 70-200mm f2.8 – and now it’s joined by the com­pan­ion G2 24-70mm f2.8, sim­i­larly up­graded both in­side and out.

The new lens’s full model des­ig­na­tion of ‘SP 24-70mm f2.8 Di VC USD G2’ pro­vides some clues to what’s changed which, in re­al­ity, is pretty much ev­ery­thing ex­cept the fo­cal range and max­i­mum aper­ture. ‘Di’ is Tam­ron’s in­di­ca­tor for its lenses de­signed for imag­ing onto full-35mm for­mat sen­sors (as op­posed to ‘Di II’ for the ‘APS-C’ for­mat mod­els), but ‘VC’ is more in­ter­est­ing be­cause it stands for ‘Vi­bra­tion Com­pen­sa­tion’. which is Tam­ron’s op­ti­cal im­age sta­bil­i­sa­tion sys­tem. Sta­bil­i­sa­tion was once gen­er­ally only in­stalled in longer fo­cal length lenses be­cause they in­her­ently have more is­sues with cam­era shake, but Tam­ron puts its VC units in many shorter zooms where, in re­al­ity, they can be equally ad­van­ta­geous when shoot­ing hand-held. Short fo­cal length lenses are still used in low light sit­u­a­tions, right? The pre­vi­ous model was also sta­bilised – the first in this class, ac­tu­ally – but the G2 ver­sion is now con­trolled by a more ad­vanced mi­cro­pro­ces­sor which en­ables up to five stops of cor­rec­tion for cam­era shake. This means you can go as slow – in terms of shut­ter speeds – as is prac­ti­ca­bly pos­si­ble, mak­ing full use of the f2.8 max­i­mum aper­ture when shoot­ing at dawn or dusk, in­doors or even with some night scenes. Ad­di­tion­ally, the new sys­tem au­to­mat­i­cally switches be­tween nor­mal and pan­ning modes, based on anal­y­sis of the cam­era move­ment.

GLASS WORKS

A sec­ond high-pow­ered mi­cro-pro­ces­sor is tasked with aut­o­fo­cus­ing du­ties – that’s the ‘USD’ ini­tials in the model num­ber – pro­vid­ing faster and more ac­cu­rate con­trol of the drive sys­tem which, as is now the case on most higher-end AF lenses, uses ul­tra­sonic pulses.

Like the com­pan­ion SP 70200mm f2.8, the G2 24-70mm f2.8 has a weather-sealed bar­rel con­struc­tion with a flu­o­rine coat­ing on the front el­e­ment’s ex­posed sur­face to help re­pel dust and mois­ture. The main tubes are metal al­loy and, at 900 grams, this lens feels pretty sub­stan­tial in the hand.

On the in­side, the op­ti­cal con­struc­tion com­prises 17 el­e­ments in 12 groups, of which a to­tal of nine are spe­cial types. This is where lens de­sign has made sig­nif­i­cant ad­vances over re­cent years and why the G2 lens is guar­an­teed to out­per­form

its pre­de­ces­sor. Four of the spe­cial el­e­ments are as­pher­i­cal types – three made from glass­mould­ing and one us­ing the hy­brid tech­nique which uses a spher­i­cal glass core over which is coated op­ti­cal resin to shape the sur­faces – and these work to­gether to cor­rect for dis­tor­tion. Five of the spe­cial el­e­ments ei­ther have low dis­per­sion char­ac­ter­is­tics or a high re­frac­tive in­dex, which col­lec­tively en­sure all the wave­lengths of vis­i­ble light travel through the lens in the same way in or­der to min­imise chro­matic aber­ra­tions – both ax­ial and trans­verse – and spher­i­cal aber­ra­tions. Two of Tam­ron’s mul­ti­coat­ing tech­nolo­gies – ‘eBAND’ and ‘BBAR’ – are em­ployed to min­imise in­ter­nal re­flec­tions (in­clud­ing those com­ing off the sen­sor’s sur­face) and also re­duce both ghost­ing and flare. A bay­o­net­fit hood is supplied to fur­ther help with pre­vent­ing the lat­ter and, in­ci­den­tally, em­ploys a new lock­ing mech­a­nism so it’s harder to ac­ci­den­tally knock it off.

The min­i­mum fo­cus­ing dis­tance is 38 cen­time­tres which, at 70mm, gives a max­i­mum mag­ni­fi­ca­tion ra­tio of 1:5. The di­aphragm has nine blades to give a more rounded aper­ture and hence smoother out-of-fo­cus ef­fects. It’s elec­tro­mag­net­i­cally con­trolled in both mount ver­sions – Canon EF and Nikon (G type AF) – which means, for users of the lat­ter’s D-SLRs, that aper­ture set­ting has to be pos­si­ble from the cam­era body.

PER­FOR­MANCE

Tam­ron’s G2 lenses have much more con­tem­po­rary styling with flush-fit­ting con­trol rings and a satin fin­ish. It’s prob­a­bly no co­in­ci­dence that there’s a hint of Sigma’s Art lenses in the ap­pear­ance of the new 24-70mm f2.8, par­tic­u­larly the in­set metal ‘SP’ badge on the side of the bar­rel (sim­i­lar to the Sigma’s ‘A’). The build qual­ity and fin­ish are cer­tainly com­pa­ra­ble.

The zoom­ing col­lar has a lock­ing switch while the fo­cus­ing col­lar pro­vides a full-time AF over­ride which en­gages im­me­di­ately that it’s turned. Both are nicely weighted, al­though the lat­ter is a ‘fly-by-wire’ elec­tronic con­trol. A bin­na­cle ahead of the lens mount car­ries AF/MF and VC ON/OFF switches.

By happy co­in­ci­dence, Nikon’s D850 ar­rived for test­ing while we still had the G2 24-70mm f2.8, so it was the per­fect op­por­tu­nity to try it out with this cam­era’s 47.5 megapix­els sen­sor and its high-per­for­mance AF sys­tem. The two got on very well in­deed. The aut­o­fo­cus­ing was as fast and as re­li­able as with the cur­rent AF-S Nikkor 24-70mm f2.8E ED VR, which is both sig­nif­i­cantly big­ger (par­tic­u­larly in length), heav­ier and more ex­pen­sive. The con­tri­bu­tion of all those spe­cial el­e­ments is very ev­i­dent in the im­age qual­ity, par­tic­u­larly the uni­for­mity of sharp­ness across the frame, re­gard­less of the fo­cal length and across the aper­ture range to f16 (at f22 dif­frac­tion takes the edge off the def­i­ni­tion). Over­all though, this lens clearly doesn’t have any is­sues deal­ing with ul­tra-high sen­sor res­o­lu­tions. Uni­for­mity of bright­ness is also very good, and al­though some vi­gnetting oc­curs when shoot­ing at f2.8, it’s a lot less than is of­ten the case, and is elim­i­nated by stop­ping down to f4.0. Dis­tor­tion is mostly well con­trolled al­beit with some bar­rel­type bend­ing ev­i­dent at 24mm and very slight pin-cush­ion­ing at around the 50mm mark. The bar­rel dis­tor­tion is ac­tu­ally a bit more pro­nounced than we would have ex­pected, but ob­vi­ously can be eas­ily cor­rected post­cam­era. Chro­matic aber­ra­tions are vir­tu­ally non-ex­is­tent even in con­trasty sit­u­a­tions when shoot­ing wide-open, and this is a key area where the new op­ti­cal de­sign is su­pe­rior to both the pre­ced­ing lens and a num­ber of com­peti­tors.

THE VER­DICT

Tam­ron’s G2 70-200mm f2.8 puts it firmly back in the game in that cat­e­gory of sta­ple ‘work­horse’ zoom, and the G2 24-70mm f2.8 is sim­i­larly a se­ri­ous com­peti­tor to the key ri­val mod­els from Canon, Nikon and Sigma.

What Tam­ron’s new con­tender has go­ing for it is the ex­tended ca­pa­bil­i­ties of its im­age sta­bil­i­sa­tion, good close-up ca­pa­bil­i­ties, high-end build qual­ity, ex­cel­lent over­all per­for­mance and, in the light of this, great value for money. The one nig­gle is the amount of bar­rel dis­tor­tion at 24mm, but it’s still com­par­a­tively small and so won’t be an is­sue for many users. Tam­ron con­tin­ues to go from strength to strength.

STA­BIL­I­SA­TION WAS ONCE GEN­ER­ALLY ONLY IN­STALLED IN LONGER FO­CAL LENGTH LENSES, BUT TAM­RON PUTS ITS VC UNITS IN MANY SHORTER ZOOMS WHERE, IN RE­AL­ITY, THEY CAN BE EQUALLY AD­VAN­TA­GEOUS WHEN SHOOT­ING HAND-HELD.

TAM­RON SP 24-70mm f2.8 DI VC USD G2 ZOOM

Large-di­am­e­ter front el­e­ment has a flu­o­rine coat­ing on its ex­posed sur­face to help re­pel dust and mois­ture, and al­low for eas­ier clean­ing.

Bar­rel-mounted switches en­gage the VC im­age sta­bil­i­sa­tion (which has au­to­matic mode se­lec­tion) and se­lect the fo­cus­ing mode.

Lens bar­rel tubes are now metal al­loy with a smart satin fin­ish. Man­ual fo­cus­ing col­lar pro­vides a full-time AF over­ride.

Weather-proof­ing mea­sures in­clude a sub­stan­tial rub­ber gas­ket around the lens mount.

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