Physically, here are the differences:
MWD: Minimum working distance (front element to subject)
Sigma 150: 7.6" (194mm)
Sigma 180: 9.4" (238mm)
Weight:
Sigma 150: 895g
Sigma 180: 965g
As you can see in this image, the Sigma 180 is quite a bit longer than the Sigma 150, but only about 70g heavier. However, as you will find out later, the extra 30mm does makes quite a lot of difference!
I didn't think the extra 30mm would create any significant difference, until one fine day when I shot one same caterpillar with a Facebook friend of mine from Singapore. I used a 150mm whereas he, a 180mm. As you can see, the extra 30mm really rendered the background more out-of-focus, and made the subject stand out!
Both images shot with natural light and the use of a reflector.
Another comparison shot. You can see clearly that at the same magnification (the flower was similar in size in both images), the 150mm saw more of the background, or in other words, had bigger FOV (Field of View), compared to the 180mm. The dark, vertical bars were my front gate. The 150mm saw four vertical bars whereas the 180mm saw only 3 bars. The working distance was different since with the 180mm, I had to move the camera/lens/tripod a little bit further away from the subject/flower.
Check out the "truck and barn" series of images in this link for a great illustration of the same point.
You can calculate the FOV by using the calculator on this site:
So on my 40D, the FOVs would be:
150mm: 8.465° x 5.649°
180mm: 7.058° x 4.709°
The Sigma 180mm is only 70g heavier, but a couple of hundreds (USD) more expensive. However, the extra 30mm clearly buys you much better ability to isolate the subject from the background. The extra working distance is great for shooting more skittish macro/close-up subjects too!
Edit: another comparison shot. I found the same frog again. The 180mm image was shot at F10 whereas the 150mm image F8. More or less the same magnification as the frog looks about the same size in the images. The 180mm image was slightly cropped on the left. So consider the slight crop and the higher F number a handicap to the 150mm :D. Again, it's easy to see that the 180mm has a much better bokeh!
Both images shot with natural light and the use of a reflector.
Great work on the comparison, there are everywere optical comparinsons of these lenses, so doing a aproach of the practical aspects of the use and the results possible with each lens is a great way to stand out the reviews, now I know the difference by the point of view of the photographer.
ReplyDeleteThanks Han Yang, Gustavo.
ReplyDeleteGustavo, I was told that the Tamron 180 gives better bokeh and most of my butterfly chaser friends use that lens. I hope I can borrow one for comparison soon :)
Will surely be a positive thing, and would be nice to hear your opinions, the Tamron 180mm have reputation for excellent optics.
ReplyDeleteFantastic illustration of the differences between the 2 lenses. Thanks Kurt.
ReplyDeleteGustavo - I'll try :)
ReplyDeleteMel - thanks. NL is so much fun. Challenging at times especially when it's windy and/or subject wouldn't stay still :D, but i love the light.
Man,you have a really great Blog, Thanks for sharing all this images and information. Hope you don´t mind to include a link to your site, from my blog.
ReplyDeletehttp://diversidadentrependientes.wordpress.com/
Greetings!
Sigma 180 - want!
ReplyDeleteIt's an awesome lens especially for natural light macro. You should get one, Ted :)
ReplyDeleteNice comparison in both lens. Oh man, poisoned with 180mm....
ReplyDeleteThanks Andy. I sold the 180 already, left with 150 now. But it's lighter and more handheld friendly :D. And i can always add a 1.4x teleconverter to get 210mm.
ReplyDelete