Also remember that you can afford to raise the pixel noise with the extender. Because the image is larger. With the same pixel noise, the larger image will always look better after down-sizing both to the same size
The larger image shot with extender, will look better if they have the same pixel noise levels. So you can afford to raise the pixel noise in that because you will have more to down-size
Mar 13, 2010 at 12:40 PM
Lars Johnsson Offline • • • • • • • Upload & Sell: Off
mh2000 wrote:
it's nice to frame to your final image in the VF using the whole VF too...
Yes it will be more easy to make a good composition. If cropping you can't even be sure what will be inside or outsite the edge when you shoot
I don't think the TC is obsolete. But it's fairly clear that higher resolution (used with the required additional care) has made them less of a necessity than they were in the past with digital SLRs.
Nill Toulme wrote:
Vagrant thought for a Friday evening... We used to see the question come up occasionally of whether it was better — i.e., the less objectionable compromise — to use an extender or to crop. The consensus was generally that the extender beat cropping, in most cases and with most combinations of equipment.
But I don't think I've seen such a comparison done recently, with Mark III and later bodies. We now have more resolution and therefore more cropping leeway, and the flip side is that the higher resolution also requires more quality from our lenses.
Any chance that in the case of the Mark IV, for example, these two factors might combine to render extenders "obsolete?"
Here's a moonshot with stacked 2x TCs on the 400 2.8 IS, using the smallest EOS pixel size currently available. Seems to me that TCs will still be useful for a few more years, at least for bright, sharp primes.
MANILA MOON - MARCH 7, 2010. Observed from Paranaque City, Philippines, on March 7, 2010 (04:57:54 local time), Canon 7D + 400 2.8 L IS + stacked Canon 2x and Sigma 2x TCs, 1600 mm, f/16, ISO 100, 1/25 sec, contrast detect focus in Live View, 475B/3421 support, remote switch, processed, cropped and resized to 75% of actual pixels.
No, of course not. A picture taken at 100 mm is completely different than taken at 140 or 200 mm. The whole image gets compressed using a longer focus. This has imo nothing to do with resolution.
DavidP wrote:
I don't think the TC is obsolete. But it's fairly clear that higher resolution (used with the required additional care) has made them less of a necessity than they were in the past with digital SLRs.
It would be great to avoid a 2x TC if possible. I still think a 1.4x is a must have and on the good glass the drop in IQ is not worth worrying about, but a 2x can be more problematic and your technique for getting a sharp shot from a supertele + 2x needs to be very good. Still having said that I've gotten some very nice results using a 2x but that was with my low density 1DII. The 7D gets me almost he same reach sans 2x.
alundeb wrote:
I guess we will have different opinions, but at first glance the image quality looks best at 600mm ISO 400, even though the resolution is higher at 1200 mm ISO 1600. If someone wants to process the images for better interpolation or noise reduction, feel free to do so and share the results.
you do bring up a good point, if the conditions are not ideal and you push things too far with TCs and need to bump the ISO way up the overall look can be worse and at some point the noise will entirely eat any any resolution advantage anyway, even if it didn't quite yet in that example
the middle does look best
perhaps though a 2x + 1.4x would've come out better than the 2x + 2x or 2x
i'm surprised that even the 2x+2x showed more detail than the 2x on a 7D, i really would've expected a lone 2x TC to be the limit (then again you did stop down way a lot, few people can ever realistically shoot wildlife or sports like that).
alundeb wrote:
In this case a 2x + 1.4x would have come better out, but I didn't take it at ISO 800, so I can't show a direct comparison.
Even though I stopped down 1 1/3 stop, most of the gain in sharpness comes from the first two 1/3 stops, from there the differences are smaller.
Get ready for another surprise:
2x+2x is still not the limit for this lens on the 7D.
Here is the full range from bare 300 magnified 5.6 times, up to 1680 mm (2x+2x+1.4x). All stopped down one stop, and sharpened equally after resizing.
I can only imagine how this would have looked without the degradation from the 3 stacked teleconverters. When people say 15 - 20 MP is enough, my reflex is to object instantly. If a FF camera was made with a pixel density correspondig to this resolution, in other words outresolving the 300 2.8 IS without teleconverters, it would have 1500 MP.
1.5 gigapixels. Look at the 'G'. ...Show more →
That's pretty remarkable!
I think i need to get myself a second TC. I won't push it that far since it's often too shadowy or gloomy to get enough light, but maybe I should even go for a 2x instead of a second 1.4x TC.
I wonder how 1.4x+1.4x stopped down 1 stop (f/8) does compared to 1.4x+2x wide open (f/8)?
I wonder if 1.4x+1.4x really is any better than 2x for either IQ or AF as some say.
