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New Sigma 18-300 sharper than older Sigma EX F2.8 lenses

Discussion in 'Lens Matters' started by sam.spoons, Nov 20, 2019.

  1. sam.spoons

    sam.spoons Active Member

    I have just bought a SIGMA 18-300 MM F3.5-6.3 C DC MACRO OS HSM lens to go on my (2x) Canon 50D bodies. I also have Sigma 17-35, 35-70 and 70-200 DG EX f2.8 lenses (and the 2X convertor for the 70-200). I'm very perplexed as I've been shooting some test shots, tripod/still life, to see how the new lens stands up against the 'proper kit' and in all the tests the new lens is much better! I'm just a casual amateur doing this for fun but am in the position of being able to afford some nice kit (and, TBH, I need all the help I can get). All my old full frame lenses are 15 years old or more, and all were bought used but I expected them to be better than the new 'all in one' zoom. Am I missing something or should I just sell all the 'posh kit' and just have the one body and lens?

    Would having the old lenses professionally cleaned be worthwhile, the 70-200 shows a little internal marking/dust/fungus (it's the hardest used and, probably, oldest of the lenses, shows a fair bit of wear and was bought from a semi pro sports photographer) but the others only have a little external dust/fingerprints visible on the front elements and are, otherwise, almost like new.
  2. Andrew Flannigan

    Andrew Flannigan Well-Known Member

    The newer the lens the better the design should be. Sigma are known for good designs all too often badly implemented. When you get a good one they're really good but I had two of their ultrawide zooms in a row that displayed noticeable decentering. On the other hand I used an old 28-300 for years on a full frame and was very pleased with the results. (what's more it only cost me £60)

    There used to be retailers like R.G. Lewis that supplied a test certificate with every lens so you knew just what you were buying be it new or secondhand. Such service is no longer available so far as I know. :(
  3. sam.spoons

    sam.spoons Active Member

    Thanks, I'm going conduct do a more thorough test later but am in a quandary, there is no point in having the old, heavy, expensive lenses if the new, lightweight, cheap (relatively) lens does everything better.

    When I bought the 70-200 the guy showed me some images taken with it on a 1D-S (presumably a mk1 or mk2 given when I bought it) and they were pin sharp down to pixel level. I also had an older Sigma 18-200mm f3.5-5.6 and Canon 20D bodies, it was good but the big lenses were better so the new 18-300mm is remarkable.

    So, if I decide to sell the old f2.8 lenses what do I buy to replace them? Or do I simply not bother and buy a nifty 50 for the second body........
  4. El_Sid

    El_Sid Well-Known Member

    The question is: Are the old lenses bad or just not quite as good as the new one - particularly at real world print sizes? The thing to remember is that the old lenses were designed for film whereas newer lenses are designed specifically for the resolution demands of current high pixel count sensors which can be more demanding and more unforgiving with regard to lens resolution.

    One advantage of the older lenses is the larger maximum aperture which gives you additional options with shallow DOF and in the right circumstances may allow the use of lower ISO thus reducing noise issues.

    If you were to replace them then logically the options would be the the current Sigma equivalents or the Canon versions - unless you fancied buying a bunch of primes...;)
  5. sam.spoons

    sam.spoons Active Member

    Thanks. Max aperture certainly is a big plus, and the reason why I bought the EX lenses I have. Is it possible/reasonable to get the 70-200 serviced and cleaned? Could it be that the AF is off (but in all three EX lenses)?

    I might consider a couple of primes and a big zoom as an alternative to the three f2.8 zooms, (harking back to my old Minolta film setup, SRT 101 and later X700 with 24mm f2, 58mm f1.2 and 70-200 f3.5 zoom).

    I probably need to re-evaluate what I will do with my photography now I'm starting to get back into it. Partly 'cos # one (grown up) son has just started to become interested so hopefully it's something we can share.
  6. PeteRob

    PeteRob Well-Known Member

    I would suggest you get a quote for the lens cleaning, it is fairly standard to have a charge of £30 or so even to have someone look at the item. If they are old lenses then parts may not be available - and you'll only find that parts are needed when it is stripped down. I'd expect some low hundreds of pounds, labour is probably £100 an hour. I know its not a lens but a motherboard replacement on my Canon 5Ds cost £700. That was by Lehmann in Stoke-on-Trent via LCE.

    Sigma are trying to move up the quality ladder. It surprises me a bit that an 18-300 mm is "better" than a 70-200 F2.8 but indeed it depends on how old and worn that lens is. If you compared with the latest Canon 70-200 F2.8 L IS you might have a different story.
  7. sam.spoons

    sam.spoons Active Member

    I probably worded that badly, the 18-300 appears sharper than the old EX lenses but I haven't done any meaningful comparisons WRT other benchmarks yet so 'better' was maybe a bad choice of word. I will do some more detailed comparisons in the next few days. FWIW I do realise that sharpness is not the only critical factor (though I'd say it is pretty important).
  8. PeteRob

    PeteRob Well-Known Member

    Most important thing is that you are happy :)
  9. sam.spoons

    sam.spoons Active Member

    :) it is indeed
  10. sam.spoons

    sam.spoons Active Member

    So I've got my eyes on a Canon 5D mk2 to allow me to make use of the wide end of my Sigma EX 17-35mm. The thought occurred that if the resolution of the sensor is greater than the resolution of the lens the extra pixels are wasted? I could save a lot of money by buying a 12MP 5D mk1 instead of the 21MP 5D mk2.
  11. PeteRob

    PeteRob Well-Known Member

    I'm not sure that I buy into sensors out-resolving lenses. The only practical implication of having 21 rather than 12 MP is that prints can be twice the area. If the Sigma is so soft at tbe wide end that it'll look poor with images printed to A3 then (assuming this is what you want to produce) get a better lens. Given a choice I'd always go for a higher pixel camera. It gives more freedom to crop.
  12. sam.spoons

    sam.spoons Active Member

    That's what I thought bt only if the lens resolution exceeds the pixel count. I know the EX lenses can produce great images which should be sharp down to pixel level but I'm still trying to work out why mine all appear softer than my cheaper 18-300. It must be something I'm doing but I can't for the life of me work out what.
  13. sam.spoons

    sam.spoons Active Member

    Put another way, if the lens is really sharp then zooming in to pixel level won't reveal any softness, if it appears soft before that then is the lens sub-par?

    FWIW an image at glossy magazine centrefold size would be roughly A3 and would only be about 6MP (at 300 dpi).
  14. PeteRob

    PeteRob Well-Known Member

    Yes, but there is a price-performance consideration.

    I swapped a EF 17-40 for an EF 16-35 and you can see the difference if you really look for it. The 17-40 was the goto landscape lens when I bought it. Just about every landscape picture published double spread in the magazines used it.

    I use a 5Ds now. It doesn't mean I chuck out what I took with a 5D and I've printed A3+ from hard crops on that.
  15. El_Sid

    El_Sid Well-Known Member

    It may just be a matter of lens calibration. Sigma reverse engineer their version of the EF mount so it's quite possible that the firmware in the old lenses doesn't quite match that in the newer lens when it comes to adjusting the focus movements to the reported distance. I note the new lens is the HSM type, these also seem to offer better precision in fine focus than the older mechanical drives did - a case of spot on rather near enough is good enough...
  16. sam.spoons

    sam.spoons Active Member

    I though that may be the case but have not managed to manually focus for a sharper image, will try again when I have better light as my last attempt was on a dull day (and rather hurried).

    Two of my three EX lenses are HSM (17-35 and 70-200) the other (28-70) is not so I'm not sure that is making a difference. It may be that he HSM motor drives are improving though so it may be the newest version is simply better.
  17. SqueamishOssifrage

    SqueamishOssifrage Well-Known Member

    I do tend to match the resolution of camera to lens, using the LenScore and SensCore facilities on www.lenscore.org website. Not all cameras and lenses are covered, but my camera bodies are rated at 736 for resolution, so I tend to buy lenses with around that resolution - 24-70mm @ 755, 28-75mm @ 694, 70-300mm @ 723 and so on.

    I also have the Sigma 17-35mm EX DG, and rate it's resolution as less than the 24-70mm but a good match for the 28-75mm at 694, or perhaps a little lower. The Canon 5D II is rated at 669, so it looks a reasonable match to the Sigma lens. Note that these are all resolution figures, not overall performance, and cover a wide range of potential use.

    It may not be terribly scientific, but it does at least point out that there is little point in me buying, for instance, a Zeiss 50mm f:1.4 Milvus @ 1036 and £1,000 versus my Sony 50mm f:1.4 @ 787 and £330. I would probably notice an improvement, but not 30% improvement based on the resolution score, and certainly not a 300% increase based on price!
  18. sam.spoons

    sam.spoons Active Member

    Interesting site, thanks for the link. As it happens none of my lenses are on there, nor my 50D but it'll be very useful when/if I decide to change.
  19. AndyTake2

    AndyTake2 Well-Known Member

    Sigma will upgrade the firmware for a small fee covering postage, or for free if you go there.
    Some lenses can't be done due to age. I had some done last year apart from two, one a 180 f3.5 macro, and the other was a wide zoom, can't recall which one offhand.
    Certainly worth trying, as the autofocus may work a bit better.
    I was told by Sigma that the older lenses are not up to newer sensors.
  20. sam.spoons

    sam.spoons Active Member

    Thanks, will contact them. :)

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