Fergus wrote:
Has anyone been following the new Tamron 18-400 F 3.5-6.3, or better, has anyone purchased one?
Don't have one and will never buy one.
Image quality is pretty poor compared to the less radical range 24-70, 70-200 and 100-400 zooms I use. The Tamron is okay in the center of the image, but soft toward the edges and corners. And it has tons of chromatic aberration at longer focal lengths. See for yourself:
https://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=1145&Camera=963&Sample=0&FLI=5&API=1&LensComp=972&CameraComp=963&SampleComp=0&FLIComp=4&APIComp=1https://www.the-digital-picture.com/Reviews/Tamron-18-400mm-f-3.5-6.3-Di-II-VC-HLD-Lens.aspx Hyper-range zooms like the 18-400mm give you the convenience of "all in one", but they compromise in an awful lot of ways, too.
- Small aperture... starts out at f/3.5 at 18mm, but drops to f/4.5 at 42mm, f/5 at 50mm, f/5.6 at 89mm and all the way to f/6.3 at 117mm. At a lot of its focal lengths, it's a full stop slower than my slowest lens. As a result it would be a "good light only" lens.... and shooting sports and wildlife, that just won't do for me.
- Adding a filter like a circular polarizer would make for an even dimmer lens.
- Lens hood is shallow to avoid vignetting at 18mm... it cannot possibly be very effective at 200, 300 and 400mm!
- It's good that it's internal focusing (doesn't increase length when focused closer)... But it's far from internal zooming. It doubles in length when zoomed to 400mm.
- No tripod mounting ring... can't imagine using a 300mm or 400mm lens without one!
- Plastic construction without any sealing for weather or dust resistance to speak of.
- When I only need 18-50mm range, seems a pain to carry around a much bigger lens.
- It's a "Di II" lens, meaning it's crop only. Can't use it on full frame cameras.
- Seems okay when new, but might develop a rather severe case of "zoom creep" when it gets some wear and tear on it and loosens up. Has a zoom lock, but it only works at the fully retracted (18mm) zoom setting.
Granted, there are some things it does pretty well, all things considered...
- Close focusing.... gets to about 1/3 life size (at 400mm), which is better than many zooms.
- For it's range, it's reasonably compact and light weight.
- Pretty nice "bokeh" at the longer focal lengths, though the strength of background blur is limited by it's small max aperture.
- Faster focusing than I expected.... though it's dependent on good light (might be okay on newer cameras that can focus down to -3EV or even lower).
- Image stabilized, though it's less effective than most (Tamron claims it's good for up to 2.5 stops... most stabilized lenses today are rated 4 or even 5 stops).
- A lot less to carry around, compared to the three lenses I mentioned (or many other combos).
- At $650, it's a lot of focal lengths in one, for the money.
Actually, it's a pretty amazing lens, offering a previously unheard of all-in-one zoom range. If you only have a very limited budget for lenses.... And if you don't have very high expectations of image quality, never crop your images much and don't make very large prints from them... Or if you're traveling and have a severe limit on the camera gear you can carry.... Or if you are simply too lazy or scared to change lenses... It might be a good lens for you. It's not for me.