In this week's video tutorial you will learn about the various benefits of processing your RAW files in an editing program. Paired with the advantages of shooting in manual mode, this important step...
The Tamron SP 180mm f/3.5 Di LD (IF) 1:1 Macro Lens for Canon, (compare prices) is a macro lens that will focus down to 1x magnification. That means it will image an area 36mm x 24mm when used on a full frame (D)SLR or around 23mm x 15mm when used on a Canon APS-C DSLR. It’s also a regular 180mm telephoto lens of course (with full frame equivalent focal length of 288mm when used on a Canon APS-C DSLR). It’s available in mounts for Canon, Nikon and Sony (D)SLRs
The Tamron 180/3.5 has a couple of unusual features. First is the manual focus switching mechanism. When you push the focusing ring forward, the lens is in autofocus mode, but if you pull it back it switches to manual focus mode. This does make switching between AF and MF a little quicker than having to use a switch on the lens or camera since you’re already holding the focusing ring when you switch to manual focus. However you can’t really autofocus and then switch to manual focus without slightly changing the focus setting, since you inevitably turn the focusing ring slightly when pulling it back.
The second unusual feature is that there is a ring right at the front of the lens which turns the filter threads. This is very convenient when using a polarizer on the lens with the deep lens hood attached because otherwise you’d have to remove the hood to turn the polarizer!
The tripod collar can be removed, which makes handholding the lens a little easier.
The Tamron 180/3.5 does not have any image stabilization and the focusing motor is a regular geared motor, so it’s not as fast as an Ultrasonic motor and it makes more noise. For macro work while IS can be useful, it’s generally less effective than at longer focus distances and a tripod is almost always better. However IS for general use as a handheld telphoto lens would be quite useful.
The main advantage of a macro lens with a long focal length is that there is more distance between the subject and the lens when you are close focused at 1x magnification. This distance is called the “Working Distance” and is about 10" (25cm) for the Tamron 180/3.5 Macro. A longer working distance makes it easier to get light onto the subject and allows macro images of subjects (insects and small animals) that might be disturbed if the lens was closer to them.
Tamron 180mm f3.5 Macro Specifications
Maximum: f/3.5, Minimum: f/32
Available Lens Mounts
Canon, Nikon, Sony
Minimum Focus Distance
1.54ft (47 cm)
Minimum Working Distance
About 10" (25cm)
Approx. 3.3 × 6.5" (8.38 × 16.51 cm)
2.02 lb (920 g)
Tamron 180mm f3.5 macro LD-IF performance
The measured autofocus speed on an EOS 7D was 1.8s from closest focus to infinity. From 4ft to infinity (or infinity to 4ft) took just 0.35s. It’s unfortunate that the Tamron 180 macro doesn’t have a focus limiter switch, since if the camera has a problem finding focus or goes the wrong way when searching, it can take several seconds for it to rack through the focus range. Focus was accurate, even in the macro range, with occasional overshoot and correction being observed.
Vignetting at f3.5 on an EOS 5D full frame camera was about 1.3 stops with the lens focused at infinity and 0.3 stops at closest focus (1:1). Stopping down to f5.6 the vignetting at infinity focus was about 0.5 stops and at closest focus vignetting was less than 1/3 stop.
For a given light level, the Tamron 180 macro required about 2.3 stops more exposure at closest focus (1:1) than it did when focused at infinity. This is normal for macro lenses. Canon cameras display the physical aperture of the lens at all times (e.g. f3.5) rather than the effective aperture for metering (which in this case, at f3.5, would be around f8). Camera metering and auto exposure takes care of this of course, so there are no exposure issues, at least not unless you are using manual exposure with an external exposure meter.
Full image, EOS 5D, Tamron 180mm @ f16. Closest focus (1:1), 1/6s @ ISO800
Resolution on an EOS 7D at 1:1 was over 80 lp/mm from f3.5 to f8 with slight peaking at f5.6. At smaller apertures the effects of diffraction were visible and resolution decreased. F11 and f16 were not too bad, but at f22 the image was noticeably diffraction softened. For those who think in terms of LPPH (lines per picture height) 80 lp/mm would correspond to 2384 LPPH. This is more of a sensor limitation than a lens limitation since visual examination of the aerial image formed by the lens showed an intrinsic resolution of over 228 lp/mm (which is the group 7 element 6 limit of my USAF 1951 chrome on glass macro resolution target).
100% crop from image center. EOS 5D, Tamron 180/3.5 at f5.6, 1/1000s @ ISO 400
In the non-macro range the Tamron 180/3.5 contrast is a little lower at f3.5 than at f5.6 in the center of the frame but the resolution doesn’t change much. Optimum contrast and sharpness peaks at around f8 and I measured close to 90 lp/mm in the center of frames shot with the EOS 7D. F16 and especially f22 are noticeably diffraction softened. Image corners (full frame on EOS 5D) were slightly soft due to mild astigmatism and diminished contrast wide open, but sharpened up nicely on stopping down to f5.6 and were nearly equal to the center at f8.
Left: In focus at f3.5, Right: Out of focus at f3.5
The Bokeh (out of focus blur) produced by the Tamron 180/3.5 macro is quite smooth as can be seen from the illustration above.
100% crop from the corner of an APS-C 1:1 macro shot at f5.6 (taken using an EOS 7D)
Left: As shot, Right: After correction
Chromatic aberration is visible towards the corners of the frame, even the APS-C frame. The above image is a 100% crop of a 1:1 macro image at 80% of the distance from the center of the frame to the corner (EOS 7D, APS-C). The color fringing is 5-6 pixels wide, which is significant. CA can be minimized digitally by a number of image editors as shown on the right in the above image
Summary and Conclusions
The Tamron SP 180mm f/3.5 Di LD (IF) 1:1 Macro Lens for Canon, (compare prices) is a good lens, with high central resolution, even wide open at f3.5 and closest focus (1:1). Resolution holds up quite well even out to the edges of the frame, especially when close focused. At longer focus distances the corners wide open are a little soft but sharpen up well by f5.6. Distortion is very low and vignetting is well controlled at both normal and close focus distances. Even wide open at infinity focus, vignetting is only about -1.3 stops at the extreme corners of a full 35mm frame, which is pretty good. There is visible chromatic aberration, and that’s probably the most noticeable aberration of the Tamron 180 macro. However it can be minimized digitally if it proves to be a problem.
Focusing is rather slow, at 1.8 seconds from infinity to close focus (3.6 seconds for the “round trip”) and that could be an issue at times. There is no focus limiter so you can’t restrict focus to a smaller region (say 4ft to infinity – which only takes 0.35 seconds) when you know your subject will be at a particular range of distances (macro or non-macro). Focusing isn’t silent since the focus motor isn’t ultrasonic, though it’s not loud enough to be a problem in normal use.
The Tamron 180/3.5 macro is, as far as I know, the least expensive telephoto macro lens currently available by a significant margin. Other options (see below) are up to twice as expensive, though some of them have optical stabilization and all have ultrasonic focusing motors.