Is this lens sharp - 500 mm for 120 USD?

Hi all

I actually got that 500 mm lens a while ago for an equivalent of about 120 USD. It's a VERY slow lens, with f/7.2 as the "wide open" aperture - the Sigma 500/7.2 APO AF. But for the price, what can I say... it takes pictures, and it even autofocuses pretty o.k. when the light is good. I'm actually pretty happy with it.

However, I've been wondering whether this thing is any sharp or not when compared to other setups. I'm of course not talking about 500/4 lenses, but things like the "Bigma" 50-500 or a Nikon 300/4 with a 1.7 TC.

Well, I've uploaded two images, one shot at f/8, one at f/9.5. I think the optimum sharpness is somewhere between 9.5 and 11. They came like this outta the D50. So there is some sharpening applied from in camera processing (sharpening was set to normal), but I don't think it's excessive. Maybe the performance of the lens can still be judged...

http://n.ethz.ch/student/bgreber/npnposts/DSC_0197.JPG
http://n.ethz.ch/student/bgreber/npnposts/DSC_0216.JPG

What do you think? Tack sharp - no. But reasonably sharp? Would a "Bigma" be much sharper at 500 mm?

The reason I'm asking is the following: I might have the opportunity to get a Nikkor 300/4 (non AF-S), to which I would add a 1.7 TC to replace the 500/7.2 - for me, a major investment. So it better be clearly better than what I already have. The maximum aperture would go down to 6.8 with the TC, which is not that much better than 7.2, and I'd probably also have to stop down quite a bit on the 300/4 + TC combo for good sharpness (but would that be seriously sharper than the 500/7.2?).

Yes, that's a lot of questions. I'm simply trying to figure out whether I should stick with that old piece of glass and get the 70-300 VR Nikkor (once released) for general purpose shooting (when I can't carry the extra case for the 500/7.2), or if I should rather get a 300/4 + TC or a 80-400 VR to replace the old thing. Budget IS an issue - so please include that into your considerations.

Final tele setups would either be 70-300 VR/500 f7.2 or 55-200 DX/300 f4 + 1.7 TC or 55-200 DX + 80-400 VR (the last one actually being out of budget at the moment). What would you choose (of course, nobody can know exactly how the 70-300 VR will perform... lat's assume it works as good as the 55-200 DX, but simply up to 300)?

Thanks for your comments!

Basil

Well, I can't answer your questions about the right lens choice, but if you call those photographs "not tack sharp", then I don't really know what to say about my own lenses - both of them produce images much less sharpner than your photographs, and have been both re-tested by Canon and found "within accepted range".

I wish I could get images as sharp with my 10-22 and 24-105.

Nice shots, btw.

Thanks for your comment.

I would for example call my 105/2.8 Micro Nikkor tack sharp. This thing really delivers outstanding images. But I guess comparing a "legendary" macro lens to a cheapo tele is not a very smart thing to do on my part.

Basil

Basil, actually I am myself puzzled about the whole "sharpness" issue. Specifically by examples like yours which I come across quite often, wherein owners don't think their lenses are sharp enough - but their photos look waaayy sharp compared to mine.

The only problem is that I know my lenses have been double tested by Canon.

So is there something for me to worry about? Have I been swindled?

I haven't been able to see full-size versions of people's sample photographs. I must mention that nowadays, I almost explicitly shoot with the A-DEP feature for high depth-of-field focus, at apertures of F11-F16.

Basically my steps are:
- tripod as standard
- frame the composition, making sure the diamond falls on distinct objects or features or ridges
- switch to autofocus and A-DEP mode and press focus half-way through several times until all the points on the diamond confirm focus
- switch to manual focus and M mode with my exposure settings
- lock mirror, wait atleast 2 seconds, then shoot the photograph.

Am I doing anything wrong?

Sorry to hijack your topic, btw

I shoot Nikon and have no idea how A-DEP works. However, for static subjects, what you are doing should work perfectly fine, since you use MLU. However, at least at f/16, many lenses will become diffraction limited. So for the sharpest results, you may want to try f/8 - but you'll lose DOF.

Basil

Hi Basil,
these photos are pretty good - better than what I expected. I've tried the Bigma and the image quality at 500mm is quite similar.

The Nikon 300 f4 is surely better at 300mm, but I don't know the performance with the 1.7x TC.

I'd recommend to avoid the 80-400, I tried it with the D200 of a fried and I didn't like it at all...it has quite bad image quality (IMHO it is not much better than a cheap 70-300) and a slow, slow and noisy autofocus.

The 500/7.2 seems to have a bad reputation as far as I know, but to my eye your results don`t look bad at all. I have no previous experience with D50 files, though.

If the results from the lens (and I mean end products like prints or post-processed files) are adequate for your uses, I don`t see much reason in upgrading right away. Just because everyone on the Avian forum seems to have a 500 or 600/4 doesn`t mean you have to. If you still need better quality at reasonable cost and size/weight, you might also look at the 400/5.6 primes, used for more savings. Either Nikon`s (now discontinued) or one of Sigma`s newer 400/5.6 "Macro" variations should be better than your current 500/7.2 or most x-400/500 zooms at their longest setting.

A 400/5.6 is about the price, size and weight of a 300/4 but offers the equivalent of 600mm reach on your digital body instead of 450mm. This is already good reach for larger animals. Think of the film days - few wildlife shooters could afford 600mm prime lenses but they were still able to get some great images. When in need, you could use an 1.4x converter to get a slow, but perfectly usable 560/8.

Some argue that a combination of 300/4, 1.4x and 2x (resulting a good 420/5.6 and lower quality 600/8) would be more versatile but IMHO 300mm would be too short for most wildlife situations (almost any serious shooter I`ve seen with a 300/4 as his/her longest glass uses it with an extender anyway). For landscape-type shooting or environmental portraits, I think an x-200 should cover most purposes, especially on digital. If you already have the 55-200DX, it should do.

This is mainly based on my own thoughts when I finally decided to get a "real" long lens and have another try at shooting my local wildlife. I placed an order on a Canon 400/5.6L lens. This was two weeks ago and it should be here soon . I decided on the 400mm prime mostly for the reach/weight/quality reasons, but it was also somewhat cheaper than the more popular 100-400L IS and 300/4L IS counterparts.

This was long but hopefully worth a thought. Good luck with your decision!

Thanks for your replies. Juza - honestly, I was surprised too after buying that 500/7.2. I didn't expect anything printable coming out of it (but the A4 size prints from that lens and the D50 are really nice when properly processed). The 80-400 seems to be a mixed bag... my impression is that people either hate it or love it. Quite strange for such a lens. But thanks for the tip.

Ott Luuk - I've been looking for the Sigma 400/5.6 APO Macro for a long while, and I've never ever seen one anywhere. So I've kind of given up hoping. I'd get it in a second if I found one for a nice price.

Well, looks like I'll keep the 500/7.2 until I either win the lottery or finally get my hands on a 400 APO Macro.

Basil

Basil, I believe the older 300 f/4 (non AFS) Nikkor you have a line on does NOT work with the new Nikon 1.7 teleconverter. The newer AfS 300 f/4 - 1.7 tc would be a good combo for the money based on what I have read..

Whew, thanks Gary, good to know!

Basil