Tamron 28-75 if sp di focusing isues with canon 5d...

Discussion in 'Canon EOS' started by anna_nielsen, Nov 15, 2009.

  1. Hi there - for once in my life i decided to buy a Tamron 28-75 2.8. The thing is i sold my canon 24-70 2.8 :( to be able to affort a 70-200 2.8 USm thinking i would never miss the middelrange zoom again . A month later i did just that. Reading many many reviews i bought the 28.75 lastweek. Once i had it i did some test shots on my 5D and i couldnt get the Autofocus to focus on eyes when using multible focuspoints on either Aifocus, servo or one shot. Insteat it focused on nose, eyebrows - the things that sticks out (hope you understand:)) . when focused manually i could get supersharp images. I suspected that it had a frontfocus problems when using 5D multible focuspoints. However when i set only the centerfocus point focusing on the eyes it really made good sharp images also on 2.8. So i found this focusing chart a made some tests using only the centerfocus point , blew it up to 100% and everything , i think looks nice. Ive posetd some test images wanting you to see what you think. all shot on 75 mm : 1) 8.0. 2) 5.6. 3)4.0 4) 2.8. all with flash and 5D set to oneshot.. Should i keep it or should i get a replacement. (Really the thing is i dont understand why i dosent work on multible focuspoints as ive allways used on my other lenses. Or maybe im not using my AF correctly. Thanks for havig a look .
     
  2. first image 2.8/4.0/5.6/8.0
     
  3. It seem to me what is happening is it's doing an averaging of the over all focus/ depth of field, when you use the multiple focusing zones. Nothing wrong with the lens as I could see. Please don't take this the wrong way it's probably the user. I have found that with new equipment it take time to learn the quirks that comes with it.
    Hope this helped.
     
  4. The lens looks good. Keep in mind the 5D auto focus sensor has no way of knowing what you want in focus. If you use multiple focus points, the camera will sample all of them and then sellect a average of the focus. So there is a good chance it will not be exactly on the eye.
    If you want the eyes in focus use only one focus point (many people prefer the center focus point), set the focus mode to single shot, place it on the eye, focus, and if necessary recompose before you trip the shutter. However even when doing this the camera may still focus on the nose or something else. So always double check before you trip the shutter. Also keep in mind the focus points on the 5D are slightly larger than the focus marks in the viewfinder. So depending on lighting and contrast conditions it might focus on something at the edge of the focus sensor instead of the target in the middle of the focus sensor.
     
  5. To add to what Mike and Steven wrote: using a backfocus chart is a perfect example of when you should NOT use multiple focus points because upper, central, and bottom focus points will be trying to focus at different distances. The only time it makes sense to use multiple points is when you are indifferent as to which one locks on. The way to use this particular chart is to focus on the dark line in the center using the central focus point only.
    I did this last year with my Tamron 28-75 using the same chart, and it was right on the money. I have used the lens happily ever since. It is a great lens, particularly for the price. Enjoy it.
     
  6. Ok - Thanks all - well i agree that it certainly can be the person behind the camera and it its maybe so :) - Now ive tryied Steven F method and its actually improved it so far - i think ´(please see attacments 2.8/4.0/5.6 which is totaly raw images without any sharpening-or other pp , shot with Bowens strobe- i guess my sister i kind of tired ofthis:)) . But i must admit that this is demanding a hole other kind of concentration than shooting with the Canon 24-70 2.8 - MAYBE!. - im thinking that maybe ive become a pixelpeeper now that ive got my tamron knowing that it could have ceratin problems! Maybe my old 24-70 wasent that sharp either i cant really remember because i seldom blew it to 100%. All ths could very well be some kind of problem in my head i must admit:). Dan Koretz - thats exactly what i did - focusing with centerfocus point ONLY on the black line. - what i need is for you to tell me what you think of all my test images - do you think it compares to your speciment.Is it right on the money or do you think im crazy:)? My oppinion - i think the eyes on all images could/should be sharper. BUT applying smartsharpen really lift them . Maybe im demanding to much for the price. Only when it really locks on target manal (happend once or twice)as i said above - they are supersharp. Thanks again for all your nice replies . anna
     
  7. Just to finish this of for now - looking at the 5.6 image - one can allmost see that i focused on Her left eye and when its f 5.6 the other should be equal sharp at least and i dont think it is.
     
  8. Or maybe the eyes ARE equal sharp but because of the uneven eyelits it can confuse the viewer - hmm... have to find a "normal" person:)
     
  9. You have three separate questions: back/front focus, sharpness, and pixel peeping.
    My own view is that for sharpness, faces are not a very good test. I use images with clear lines and points of contrast, like the corners of dormer windows. With those images, a lack of sharpness is readily apparent. When I got my Tamron 28-75, I shot a series of photos of a dormer and surrounding areas, using both different f stops and different focal lengths. What I found was that if I closed the lens down at all, it was tack sharp. At 2.8 it lost some sharpness (all lenses do), but it still looked pretty good for a lens wide open.However, I use a 50D, and the crop sensor removes the far corners. The Tamron is reputed to lose some noticeable sharpness in the corners on a full frame camera.
    Re pixel peeping: it will almost always show "problems" of one sort or another. You can't compare pixel peeping on one lens to less magnified images from another.
     
  10. Ok thanks Dan . anyone in here thatt can show up a nice clean close up portrait with a Tamron 28.75 - 75mm 2.8- never mind if it had some sharpening and other pp?
     
  11. f/2.8 in the tele range will have quite a reduced depth of field. In your sample above, it is apparent that the focus is centered around the left eye on the right, but not the other eye , and not at all the nose. If the ear were visible, it would no doubt also not be in focus. The f/4 shot is much more crisp over all, due to the increased depth of field.
    A facial shot with greatly reduced depth of field will have the above characteristics. Sometimes, that is the desired effect, otherwise the f/4 in this case, is a better choice.
    It is a balancing act when choosing your aperture, to determine how much of your subject you want sharp, and weigh your choice against your focal length, your distance from your main subject, and how far distant the background objects are that you want to render out of focus.
    And yes, most lenses will provide improved performance when not used wide open. From what you show here, this lens looks pretty good wide open.
     
  12. Ok thanks Michael - i dont know what to do - first Dan says that that it lacks sharpnees - then you say it looks ok - then i find this http://www.photo.net/canon-eos-digital-camera-forum/00DFsY - i have a hard time making the decision´if i should keep it or get my money back .
    I dont really wanna get into getting a replacement which can be even worse - seems like its bigger a gamble than i thought buying a third party lens. And im in doubt that this has anything to do with depth of field - i have the 85 1.8, 50 1.4 and as i remember i could get nice focused shots on eyes down to at least 1.8! or even 1.4 maybe - . As i write im looking at a printet A3 image ive done very very closeup of my littel daughter done with my former canon 24-70 and its tack sharp at 2.8 - no uneven out of focus areas and i never really thought about it when photographing it and when i printet it - i just did. Now using this Tamron i have to use center focus point making dam sure that its focused on the eyes only to get one eye relativ unblured . hmmm......
     
  13. But smartshrpen can do wonders - applied the 2.8
     
  14. I have HAD those lenses - the funny thing is ive sold all just to be able to affort the new bowens heads which is soon on the market and a large boomarm/stand. ive bought a car battery and put it together with the travelpack batteri so my goal is to shoot alot of outdoorinviromental portraits images with strobes in daylight also meaning that i will seldom get close up portraits BUT its nice to know that it is ok and that i can get if i want. That was just some side explanation:)
     
  15. still - anyone with some nice closeup portraits with shallow depth of field bt this lens?
     
  16. Hi Anna, I uploaded a couple of examples (wedding shots) into my gallery folder at the link below:
    http://www.photo.net/photo/10191605
    http://www.photo.net/photo/10191659
    Both shots were taken with a Tamron 28-75mm @ F2.8 on a 5D.
     
  17. And also... I always use centre focus point only. I focus on what I want to be in focus then recompose. Works for me. You cannot expect the camera to zone in on the eyes with multiple focus points, as it has no clue that the eyes should be in focus - some times you may get lucky but it is like throwing a dart at a dart board with a blindfold on.
     
  18. Nice images there David - "And also... I always use centre focus point only. I focus on what I want to be in focus" - that is ok but a human has two eyes:) and sometimes the head in a portrait is angled very very slightly like the above face images how do i do that - hmm ..maybe it is the debth of field after all so one would use 4.0 or more.... i would think that 2.8 could handle that distance there is when the head is angled like that - ive been searching the net for larger portrait images made on a kind of flat face pose with this lens at 2.8 but its impossible. For me this is where a lens shows its strength and weekness - not with a smalll image res. on a ex .car 100 meters away:) With you owning this lens what is your oppininon of the raw images above?Ps . again its unlikely that i never do these kind of shots but i need to push this to make a decision if should sent it back.
     
  19. btw did i see some of those images on pbase?
     
  20. David - do you remember how this wedding couple was shot - i mean where did you or where would you place your center focus point on them to achive best image?
     
  21. For those out there who wont to buy this lens - DONT - save money and buy a real glass. If you have tryied real glass you know what autofocus and sharpness precision is . You dont have to spend a weekend test shooting charts over and over again ....
     
  22. I use a Tamron 28-75mm lens with my 5D for weddings. In fact, I have two of them because I beat the first one to death (first one now overhauled and performing flawlessly). I never use multiple focus points, however, and I don't have trouble with autofocus beyond the fact that the 5D is not the swiftest anyway. The IQ of the lens is great--the rest of it (build quality, focus speed and noise, zoom ring turns opposite) I don't find a liability. In fact, the size and weight I find, are advantages, as well as the extra 5 mm on the long end.
    I found that on the long end, f2.8 is just a shade softer, but this is true to some extent for any lens (wide open equals slightly softer). It also sharpens up nicely in processing.
    I'm surprised you used auto or multiple focus points successfully with the 24-70mm. I've heard nothing but complaints about how unsuccessful multiple focus points are, as well as the accuracy of the 24-70mm focusing (from some users, not all). Put together, I wouldn't think it would work well.
     
  23. well Nadine and everyone else including Tamron : first let me say sorry for being unfair an impatient about this lens . Yes Nadin Now hear this: I got some closeup portrait images i did take 2 month ago with the canon 24-70 and to be honest- this lens does exactly the same as my (iyes i still have it:)) Tamron when used on multiple focus points. Finding out exactly that made me do some more tests with the Tamron (i had allready called to delevery back). Now for abóut a hour 2 hours ago i made a serie of shots on 2.8 with centerfocus point and oneshot set on the 5d being very very carefull getting the right focus (yes i know its very shallow) - anyway they where all very very acceptable - infact i compared them to some of my recent shots from both the 24-70 and the 70-200 2.8 and they really kick them in the bot. first let me say ive got what we here i Denmark call "red ears" - so i must apologies (is that spelled wright?). So thank you also for learning me to use center point focus folks - it never occured to me. This last shot is 2.8/75 with a littel smartsharpen - what more can i ask for . So folks - go ahead and get that lens from Tamron. Sorry but a learned something in this forum (again:))
     
  24. and it wasent the spelling:)
     
  25. and it wasent the spelling - hope you get my point anyway:)
     
  26. Not sure if you're still reading or not but I did want to say that the common instinct to get another lens is seldom the best idea. If I had a lens that I suspected wasn't right I would rather send to the manufacturer.
    Why?
    Because that will likely be the first time an actual human (other than the owner) has ever used it and the people who inspect and adjust/repair them really know the capabilities of the product.
    I had this exact experience with my Sigma 30 1.4.
    It came back spot on in all regards and has stayed that way.
    Good luck.
     
  27. William Michael

    William Michael Moderator Staff Member

  28. "suspecion" - yes - and knowing by reading many reviews that these 3 part lenses can have problems the first thing i did was to test and test . I never did that with any of my canon lenses just took for grantet that they where ok. When that is said i must admit that using mulitple focuspoints with this lens on this particular body gives really bad results - worse than i ever had with my canon lenses.And yes the 5D focus system isent the greatets either. i can live with that. Maybe my last "eye image" is a bit oversharpend but as Nadin says : including sharpenig in pp is a part of it - just wanted to show that this lens can be really spot on - even at 2.8. It was a bit of a turn i did first saying that this lens was crap and then it is ok - but i wanted to be fair and honest and also i was very very happy to see that this actually worked. thanks again for helping out here.
     
  29. I don't have Tamron 28-75, but I do have a Tamron 17-50 as well as a Canon 17-55 (I shoot crop). The Tamron definitely takes more "steering" to get correct focus. The Canon somehow just seems to know where you want focus. I'm not sure why, but that's just the way it is.
    Don't let the focusing idiosynchracies get in the way of getting sharp photos. I too had trouble at first with the Tamron snapping onto the cheek, eyebrow, nose, or bangs. You just need to use a single AF point and point it straight at the eyeball, then recompose. A quicker method, but one that takes some skill, is to quick-focus on the face, let the lens front-focus, then while half-pressing the shutter you move the camera forward slightly to let the eye come into focus.
    FWIW my Tamron focuses correctly out of the box, but my Canon needs +12 focus adjustment in order to focus correctly. Once calibrated it does great though.
     
  30. Funny! - thats exactly the same i experience . it takes much more "steering" compared to the ex. canon 24-70 . Thats what ive been trying to explain. Now after the nice advices from you guys i do as you Arie. centerfocus point /one shot to lock focus and then recompose. And actually it gives me nice sharp images (incl pp) from 2.8 - 16 - again for the price. Ill try that quick focus method thanks.
     
  31. Btw - does Tamron mak a 17-50 or something in that range for fullframe?
     
  32. Tamron makes a 17-35/2.8-4 ultrawide for FF.
    http://www.photozone.de/nikon--nikkor-aps-c-lens-tests/288-tamron-af-17-35mm-f28-4-di-ld-aspherical-if-nikon-lab-test-report--review
    There is also a Tamron 19-35 for full-frame. This is a lousy lens, I sold mine. Avoid it.
     
  33. thanks arie
     

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