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11/20/2009 10:33:21 PM · #1 |
Can someone give me the "tell it to me like I'm 2" clarification to the difference between Di II and Di lenses by Tamron? Here is my understanding, please correct me:
The Di II is designed to be compact, with respect to its diameter, and is accomplished by controlling the image size. In other words, its designed for the smaller sensors (i.e. Canon 20D)
A Di lens is not as compact and therefore the image size would fit that of 35 mm or the larger sensors.
So, if I bought a Di II lens for my 20D and sometime later got a camera with a full frame sensor, that Di II lens will have reduced functionality due to the amount of vignetting that would appear.
So, why would one choose a Di II lens over a Di? Is it simply the trade off of focal lengths? In other words, Tamron offers 18-270 Di which on a small sensor is equivalent to 28 - 419 and the 28 - 300 Di II would thus be 45 - 480 on the same small sensor. So, in order to get the lower 28 mm, one would need a full frame sensor.
So, an 18-270 Di II is good if one will be using the small sensor camera for a while, but the Di is more versatile.
Did I get it right? :)
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11/21/2009 01:22:53 AM · #2 |
Originally posted by PGerst:
Did I get it right? :) |
Yes and no... You're correct that the DI II is designed for crop sensor cameras. You're wrong about being able to use it without vignetting in the longer reaches of the focal length; the small image circle will be present throughout, I'm pretty sure. The advantages are in weight and cost, incidentally; no need to pay for all that glass you can't use, with the cropped sensor...
R. |
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11/21/2009 03:03:58 AM · #3 |
To add to Bear_Music's explanation:
The Di II is designed for a cropped sensor camera (like your 20D). The Di is designed to be used on a "full frame sensor" camera (like the 5D).
You can use the Di lens on a cropped sensor cam without any problems. But with the 20D's crop factor (1.6 i believe on Canons), the 28-300 Di would be equal to 45-480 as you already stated. So using that lens as a "walk around lens" and you need more "wide angle", you'd have to change to a wide angle lens to get say something equal to 28mm. Where as if you had the 18-270 Tamron Di II, you would have that versatility on the wide end. So some photographers looking for a super zoom consider the 18-270 Di II to fit their needs as a walk around lens compared to the 28-300 Di (full frame lens).
On the other side of the coin. Say you have the cropped sensor lens (18-270 Di II) but you decide to upgrade to a full frame (5D) camera. (Honestly, I don't even know if the Di II lens is compatible with Canon full frame cameras.) If you are able to mount the lens and use it, the lens is designed for the smaller area of the cropped sensor. So as Bear said you'll get a lot of unusable area/vignetting on the full frame camera image. So what you have done is in reality made your 12mp full frame camera a 6mp camera and "wasted" the advantage of having a "full frame" camera. If you have a Di (full frame) lens, you take advantage of the full frame on the sensor.
Rereading your post-- why would some chose a Di II over a Di. Not as easy to explain. It depends on which Di II (crop sensor) lens or which Di (full frame sensor) lens. It depends on the photographers needs... I bought the 28-75 (full frame) lens because I wanted a faster (f2.8) lens and that lens has a acceptable range for what I wanted to shoot. I bought the 18-270 (crop sensor) lens as a "general don't have to change lenses walk around lens" and it has a wide range for that purpose. Other people (with crop sensor cameras) don't like super zooms and don't mind changing lenses and anticipate upgrading to a full frame camera and probably choose to invest in full frame lenses. It just depends on each person's needs... Hope this long winded explanation helps...
Anyone reading this feel free to correct my layman's explanation...
On a side note, I see you have the 18-270 Di II (crop sensor lens) and the 28-75 Di (full sensor lens).
I also have both of those lenses for my crop sensor cameras. I love the 28-75 for it's sharpness, it focuses pretty quick in bright light and still pretty good in low light.
I hate the 18-270 because it's soooo slow to focus in low light, lots of hunting to focus. I also think the lens isn't as sharp because (my theory) it has some "slop" on the tele end that I think causes images to be not as sharp as it should (my 2cents on that.)
Message edited by author 2009-11-21 03:29:07. |
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11/21/2009 07:42:44 AM · #4 |
Thanks. Actually, I have the 18-270 listed in my list only because I had borrowed that lens when I was in Germany and I had uploaded a couple photos with it. My primary lens is the 28-75 for the sharpness and the speed. I really did like the versatility of the 18-270 with VC, which is why I'm considering buying that lens. But, considering the information here, I'm not so sure I want to invest any money in a Di II lens...
Originally posted by The_Tourist:
On a side note, I see you have the 18-270 Di II (crop sensor lens) and the 28-75 Di (full sensor lens).
I also have both of those lenses for my crop sensor cameras. I love the 28-75 for it's sharpness, it focuses pretty quick in bright light and still pretty good in low light.
I hate the 18-270 because it's soooo slow to focus in low light, lots of hunting to focus. I also think the lens isn't as sharp because (my theory) it has some "slop" on the tele end that I think causes images to be not as sharp as it should (my 2cents on that.) |
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11/21/2009 01:20:46 PM · #5 |
Originally posted by PGerst:
But, considering the information here, I'm not so sure I want to invest any money in a Di II lens... |
I wouldn't dismiss all crop sensor lenses. As a general use walk around lens, I have the Nikon 18-200mm VR zoom. It's versatile, focuses fast, and sharp. It's the lens I have on my camera most of the time. But this is a DX (crop sensor) lens. I don't have any plans to upgrade to a full frame... (in the near future).
Canon has an equivalent 18-200mm IS zoom (DPC link for that lens) that's suppose to be pretty good. You might want to check that out if you're looking for a general purpose walk around lens...
Message edited by author 2009-11-21 13:28:58. |
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