100-400L not as sharp as 35-year old converted 400mm FD SSC lens!

I sold my cool old 35-year old, battered, manual only, non-stabilized, EF-converted, 400mm SSC f/4.5 FD lens to get a much more modern 100-400L IS lens, because I found that the lack of AF and IS was just too limiting for the types of pics I was taking.

I wanted a 100-400L, because I've always been so impressed by some very, very sharp pics from that lens, and the IS would be very useful for a shaky old dodger like myself!

But....despite the old 400mm SSC having some very visible scratches on an internal lens when they did the mount conversion from FD to EF, that lens was really incredibly sharp.

I expected the 100-400L to be even sharper, especially given the REALLY strong resolution that lensrentals.com tested the specific lens I was interested in.... one of the very few lenses with 22/22 lp/mm.

So, here's the difference, which I find pretty amazing.

The best of my "new" 100-400L shots of the moon. (Manual and AF focus ended up similar.)

IMAGE LINK: http://www.flickr.com/​photos/barrytimm/64857​28445/

IMAGE LINK: http://www.flickr.com/​photos/barrytimm/63276​45194/

Your comparing a full moon versus one that is not?

camera dude wrote in post #13523148
Your comparing a full moon versus one that is not?

98% vs 86% full. Do you think this makes a significant difference? (Hope it does!)

It does. 86% has a lot higher contrast and that leads to the picture appearing to be sharper.

So you are surprised a prime is sharper than a zoom. Why is this? My 40 year old 50mm SMC-Takumar is sharp as a razor blade, despite being twice as old as me. Just because optics are old doesn't mean they aren't good.

I noticed the same thing between my cameras/lenses that I've used to take pictures of the moon with. I had an XSi with the kit 55-250mm and the moon turned out better than when I did a 1D mk2 and a 300mm f/4L IS. I came to the same conclusion, the XSi pic was shot when the moon was ~90% and the 1D2 was shot near full. Full moon has no contrast on the surface so it appears flatter and boring. I do feel, however, that MP had a little to do with my difference too. I was able to start with more detail and crop more with the XSi's 12mp vs the 1D2's 8mp.

Doh! I would have given you better money on that 400 F4.5 SSC!
If you can live with manual focus and aperture the the best of the FD lenses give up little to the newer lenses, certainly I have been impressed with the ones I have tried!

herzi wrote in post #13523206
It does. 86% has a lot higher contrast and that leads to the picture appearing to be sharper.

OK, cool....I'll wait for the moon to wane to 86% and compare them again!

johnf3f wrote in post #13523611
Doh! I would have given you better money on that 400 F4.5 SSC!
If you can live with manual focus and aperture the the best of the FD lenses give up little to the newer lenses, certainly I have been impressed with the ones I have tried!

You must have missed my advert for that lens in the Classifieds recently....I had it yet before someone on another forum took it (admidttedly, it went very quick - in only a few hours!)

In order for this comparison to have any merit, I think you need to shoot the moon on the same night with both lenses with the same camera.

Otherwise it's like "look! these two photos of the same thing on different days taken with different lenses are different!" to which I'd say: Duh!

You're shooting pictures of something 235,000 miles away through some 62 miles of constantly changing atmosphere that happens to have a large influence on the way light travels through it.

Try again. My 100-400 is perfectly sharp as far as I'm concerned. I used only that lens this morning in fact.

IMAGE LINK: http://www.flickr.com/​photos/kurtlawson/6487​795507/

It is easier to make a good prime lens than a comparable zoom, hence the FD 400mm will perform better given similar conditions.

Have you sharpened those moon images, they look sharpened to the point of generating noise?

Can't judge from those pictures.

As others have pointed out, you need to shoot with both lenses under the same conditions. Atmospheric haze, very thin cloud etc., can make a difference to sharpness, as can the contrast of the moon surface, so you need to take both shots quite close together to have a fair test.

I also notice that you took both shots at ISO 50, but the 100-400L was at 1/250th second almost wide open whereas the 400 was at just 1/20th so was, presumably, using a significantly smaller aperture which could also improve sharpness a little. Although, to be fair, 1/20th is pretty slow to shoot the moon and I would have expected some motion blur so, from that point of view, it is maybe surprising that it is so sharp.

Try the test again, at the same settings and under the same conditions, foir a fairer appraisal.

I tried various apertures for both lenses. I must have shot 30 to 50 shots each, tweaking apertures, trying different exposures, different shutters, different ISOs,etc, etc.

I even looked up the sharpest center resolution aperture of the 100-400, which is actually between wide open and f/8, so I chose f/6.7 for that lens. I used the same sharpening on both in Lightroom, and yes, of course they've been sharpened. The pics are at 100%, with MAJOR crops to magnify the size of the moon for viewing.

This was what was common between the simple test...

1. Waited for near full moon (but NOT the same, as someone pointed out might be a primary difference in contrast, negatively affecting the 100-400 shots)
2. Used the same camera, Canon 5D
3. On the same tripod
4. With moon in roughly the same overhead position
5. Using the same wireless remote control for Mirror up shooting
6. trying different exposures, including bracketing with MUP via the remote
7. Trying many different focus attempts, primarily manual.
8. On similar, very clear, nights from the same location. No haze in either.

So, it's not by any means a perfect test, but unless the difference in contrast of the moon from the 86% vs 98% full moon makes a dramatic difference, I'm as sure as I can be that these are the best examples from both lenses, and that the old 400mm prime shows better, so far.

I do not have the old lens anymore, as I had to sell it to help pay for the 100-400, so no direct comparisons on the same night are possible, so the best I can do is to wait for the moon to be around 86% full and try the 100-400 again, for a closer comparison.

I had a feeling this thread may evoke some challenge, and believe me....I WANT my 100-400 to be better than the old lens, and I tried everything I could think of to make it a straight comparison, except the fullness of the moon was not something I'd realized was a major factor. Thinking about that now, I realize this may make a key difference and so will post the updated 100-400 pics when the moon wanes a little.

It is what it is.....