Sigma's new 150-500 MTFs - Bigma still reigns?

Telecorder · May 10, 2008

Not looking good for the 150-500 to be anywhere near the Bigma,,, such a shame...
I put the MTF charts side by side and its apparent the Bigma will still reign...
http://i33.photobucket.com/albums/d73/Telecorder/Bigma-v-150-500-MTF.jpg
http://www.sigma-photo.co.jp/lens/tele/150_500_5_63.htm
http://www.sigma-photo.co.jp/english/lens/telezoom/mf50_500_4_63.htm

Robinivich · May 10, 2008

It'd be a shame if these two (I'm thinking also of the 120-400 OS) were just the lower end line getting revamped, which is what it certainly looks like, notice no "EX" on either one, yet the Bigma and the 80-400 OS both are EX.

I'd wait though, before passing judgement by a manufacturer's MTF (though I doubt sigma would underrate their lenses)

Tee Why · May 11, 2008

The few images of the 120-400mm OS have not lived up to the expectations of this lens being a 80-400mm EX OS replacement. The price is actually under the cost of the 80-400mm lens.

I suspect that the 150-500 is not going to be a replacement for the 50-500 either.

It seems more like the 120-400 and the 150-500 are replacement or a slight upgrade to the non EX consumer grade 135-400 and the 175-500 lenses.

I'll wait for more reviews before making up my mind though.

Manfr3d · May 12, 2008

Telecorder wrote:

Not looking good for the 150-500 to be anywhere near the Bigma,,, such a shame...
I put the MTF charts side by side and its apparent the Bigma will still reign...
http://i33.photobucket.com/albums/d73/Telecorder/Bigma-v-150-500-MTF.jpg
http://www.sigma-photo.co.jp/lens/tele/150_500_5_63.htm
http://www.sigma-photo.co.jp/english/lens/telezoom/mf50_500_4_63.htm

Those MTF charts actualy look quite good. But then I've seen worse charts
from canon lenses which performed much better than a sigma with better
mtf.

claudermilk · May 12, 2008

Looks like I can ignore them now...

Telecorder · May 12, 2008

Hmmm... maybe not

claudermilk wrote:

Looks like I can ignore them now...

FWIW-->
Apparently, Sigma had posted the wrong MTF charts for the 150-500 as their posting now reflects the following...

After others pointed this out, I did a bit more reading of info on reading MTF charts and now have to say that this more in depth understanding and with the new charts, I'm changing my opinion to be more slightly optimistic about the 150-500.

Paraphrasing Canon's guidance of how to read the above MTF chart, as I now understand it--
The upper Red lines refer to a spatial frequency of 10 lines/mm (equates to Contrast or how accurate a lens' senses differences between similar shades)
The lower Green lines refer to a spatial frequency of 30 lines/mm (resolving or sensing of sharpness of fine details)
A solid line refers to sensing of lines parallel to radius from center ___ (S curves)
The dotted lines refer to sensing of lines tangential to radius ||| (M curves)
Above chart values refer to maximum aperture (most all lenses usually benefit when stopped down)
The contrast curve (upper) is the most important when evaluating differences in lenses and liklihood a lens will be a good performer

The closer the S and M (dotted curves) curves are in line, the more natural the blurred image becomes (more pleasing Bokeh).

An MTF value of 0.8 or more at 10 lines/mm (especially the Upper/Contrast/Red) curve indicates a superior lens; 0.7 -- good
An MTF of 0.6 or more at 10 lines/mm indicates a satisfactory image.

Since most of us use crop factor bodies, such as my D50, any part of the curve on the right - past ~14-mm distance from the center of the lens, is irrelevent -- as this portion is for the edges on a 35-mm FF sensor and is cropped on a crop sensor.

In the above charts, I note that the 150-500 has about equal values for the upper contrast lines and slightly better values for the resolution/lower curve. I placed colored dots on the corresponding values between the two lens for easier comparisons.

All in all, the newest calculated MTF values would seem to indicate that the 150-500 lens may have as good of an IQ as the Bigma;

perhaps better when stopped down...

Real world, hand's on reviews will tell the true story...

Manfr3d · May 12, 2008

I really wish someone would make a quality 200-400/4 or 200-500/5.6 for
Canon. Pentax had a 250-500/5.6 years ago and it seemed to be a great lens. :cry

Telecorder · May 12, 2008

Manfr3d wrote:

I really wish someone would make a quality 200-400/4 or 200-500/5.6 for
Canon. Pentax had a 250-500/5.6 years ago and it seemed to be a great lens. :cry

The Canon-mount Bigma or Tamron 200-500 would seem to be the moderately priced alternatives and, possibly, the new Sigmas -- 120-400/150-500...

Manfr3d · May 12, 2008

Telecorder wrote:

The Canon-mount Bigma or Tamron 200-500 would seem to be the moderately priced alternatives and, possibly, the new Sigmas -- 120-400/150-500...

Yes but only in focal length.

claudermilk · May 13, 2008

Telecorder: thanks for the updated MTF. Yeah, those don't look too bad & the noted the exceptional Bokeh readings o nthe new lens. I'll have to keep the corner cutoff in mind, always forget about that & that's really where this lens falls apart on the charts. Now my trouble is I'll be comparing to the 100-400L & 300/4L with 10 lines/mm lines nearly defining the top border of the chart.

Still, I guess a wait for sample images is in order.

Telecorder · May 13, 2008

Analysis Paralysis... ;-}

claudermilk wrote:

Telecorder: thanks for the updated MTF. Yeah, those don't look too bad & the noted the exceptional Bokeh readings o nthe new lens. I'll have to keep the corner cutoff in mind, always forget about that & that's really where this lens falls apart on the charts. Now my trouble is I'll be comparing to the 100-400L & 300/4L with 10 lines/mm lines nearly defining the top border of the chart. Still, I guess a wait for sample images is in order.

FWIW, here's an older subjective comparison of the Bigma v the 100-400 L that seemed to indicate that a Bigma w/OS might be equal to the 100-400 L if it had OS.

http://www.pbase.com/lightrules/bigmapump

And apparently the 120-400 OS/HSM new lens's MTF
http://forums.dpreview.com/forums/read.asp?forum=1029&message=27741691

Of course, a calculated MTF chart with values only for wide open doesn't always tell the story about the actual IQ of the system (note the MTF for the 170-500 Sigma that generally doesn't seem to live up to its calculated MTF)... http://www.sigmaphoto.com/_lenses!/popup_mtf.asp?name1=73_big.gif&name2=74_big.gif

Since the Canon mounts are expected to be released before the Nikon versions, we'll be looking to your camp to give a verdict for us guys in the dark-side camp

greggan · October 27, 2008

Sigma APO 150-500mm f/5-6.3 DG OS HSM review
My attempt to review this lens!
http://www.stockholmviews.com/sigma_150-500_os/sigmapage1.html

Homemade but it might help some to get an idea of the performance of the
new 150-500mm low budget long zoom from Sigma

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Manfr3d · October 27, 2008

greggan wrote:

My attempt to review this lens!
http://www.stockholmviews.com/sigma_150-500_os/sigmapage1.html

Homemade but it might help some to get an idea of the performance of the
new 150-500mm low budget long zoom from Sigma <img src="https://us.v-cdn.net/6029383/emoji/ne_nau.gif" border="0" alt="" >
******** src="http://shots.snap.com//client/inject.js?site_name=0" type="text/javascript"></********

Interesting read! Thanks for posting this <img src="https://us.v-cdn.net/6029383/emoji/thumb.gif" border="0" alt="" >

Robinivich · October 27, 2008

As Manfred put it, interesting read! I'm glad you're happy with your purchase!

Sigma's new 150-500 MTFs - Bigma still reigns?

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