infinity settings

[Brandon Goforth]

Another thing to consider is that the 17-40L is weather sealed, and that would seem to not only protect from moisture, but from dust as well. I too am close to upgrading to a Rebel XTi and 17-40L lens, and I've been debating between the 17-40L, Sigma 17-70, and Tamron 17-50. It seems like there are good and bad copies floating around from all 3, but if you can get a good copy of the 17-40L, it seems that overall it would be the better choice, given the images I've seen, the build quality, and the fact that it's weather sealed. By the way, you guys that own an XTi, have you had any problems with under-exposure? Seems like there have been some complaints about this.

 

[Brett Roberts]

I have quickly learned to hate the lens Market. About the time I think I have settled on a lens to purchase, I read or hear a bad review on it, not to mention once one finds one they like, there is always a slightly better one for only $100 more so I begin to consider it, only to then again consider the next step up for only another $100 more; it seems that process continues until your looking at several thousand dollar lenses. Already purchasing a new HD camcorder and SLR camera this year combined with quickly approaching college season my budget lacks the ability to afford the lenses I really want. I have quickly realized when one brings $500 to the camera shop they are not going to walk away with much glass, at least quality glass and I really hate spending that kind of money still knowing what I have is crap compared to what else it out there. Regardless of my complaints I am in need of two lenses a telephoto for wildlife needed by this fall, and a wide angle for chasing which can wait till next year. After shopping around the cheap lens market I have decided since I will use it more, I might as well stick a little more in the wide angle lens. While they are cheap telephoto lenses and not the best quality I think I am going to pick up either a Canon EF 75-300mm f/4.0-5.6 III USM or the Sigma 70-300mm f/4-5.6 SPO DC Macro currently leaning towards the sigma, anyone have any experience with either? While not as urgent as the zoom lens I want to pick up either the Sigma 10-20mm or the Canon by next Spring hmm... sounds like a good Christmas gift!!

Completely agree with you on the love/hate relationship with DSLR photography. I should've waited to get into this hobby until after college!

I've had the Sigma 70-300mm APO DG for a couple years now. For the price, it probably can't be beat. If you have the budget to get something better like the 70-200 f/4L or even EF 70-300 IS, I'd recommend going that route instead. The Sigma is capable of producing good images in the 70-200mm range stopped down some, but the autofocus is downright painful in its slow speed and loudness. The "macro" function is interesting and has yielded great results for me on a few occasions, but, like the lens itself, is cumbersome to use for various reasons. Finally, and most importantly to me, it seems to have somewhat poor contrast outdoors, even with the hood on. As I'm sure you know, you generally get what you pay for with lenses, and at < $200 for the Sigma, you can't expect a whole lot.

 

[Gene Moore]

By the way, you guys that own an XTi, have you had any problems with under-exposure? Seems like there have been some complaints about this.

As a matter of practice I now run my XTi at + 1/3 stop overexposure. Sooo, sounds to me there is some truth to the complaint. That said, it's not so clear cut. The XTi has three metering choices, center weight average, evaluative metering and partial metering. The last one, partial metering tends to be the most selective to the center of the frame and yields the darkest exposure of the three choices. Also, it's most often my selection for chasing because the center weighted average often gives me over exposed sky and perfect ground, generally that's not what I want.

Gene

 

[Mike Hollingshead]

One complaint I could make about the 17-40L is that it seems that it doesn't have the greatest contrast in the world. My canon 10-22 EF-S seems to have much better contrast. The 10-22 is also sharper.

 

[Gene Moore]

One complaint I could make about the 17-40L is that it seems that it doesn't have the greatest contrast in the world. My canon 10-22 EF-S seems to have much better contrast. The 10-22 is also sharper.

Mike, I just recently got my new EF-s 10-22 from B&H. Like you stated, the contrast (color saturation) is drastic, wow. That said, I'm not happy with the sharpness. The main problem is at 10mm....where I need it the most. It's quite sharp from the center to the left side of the frame, but soft to almost fuzzy on the right side. I believe that is attribuited to decentering of an element, at least that's what I've read. Certainly something I can't fix with a screwdriver and pliers. Sooo, ugh...do I keep it and send it to Canon, or back to B&H and maybe get something worse

. I've heard stories both ways, Canon fixed one of my lenses, but others complain they come back the same.

I hear great things about the Sigma super wide angle, but there is also a big ruturn percentage on those too. Maybe these wide angle zooms are difficult to assemble correctly? I borrowed my chase partner's 10-22 EF-s this last spring and it was spectacular all across the frame.

Gene Moore

 

[Mike Hollingshead]

I'd certainly send it back to BH for a trade. I did that with my 100-400L. If you happen to get another bad copy you can then send that to Canon. I'd just trade it in first. My 10-22 is the sharpest lens I own, and all over the image...even at 10mm.

 

[Cris Schroeder]

I initially had issues with my XTi underexposing images. I generally shoot in evaluative metering mode and the issue has gotten better.

Look at the histograms of your underexposed images. I've found that most of the underexposed shots from the XTi were shot in high-contrast situations. The camera does a great job of squeezing the shadows and highlights into the image. However, if you have some bright highlights (like bright cloud) it will underexpose to keep from blowing them out. The shadow data is there but you need to pull it out using a RAW converter.

I shot a couple of hundred frames at Arches NP, Mesa Verde NP, and the San Juan Mountains a couple of weeks ago. The Mesa Verde shots were the toughest as the mesas and cliff dwellings were in shadow and there were building thunderstorms in the area with bright sunlight. My straight JPEG conversions of the RAW files looked horrible, with the mesas grossly underexposed. I converted some of the better images twice, once for the sky and once for the mesa. Then I combined the two in Photoshop and used contrast masks to blend them together. The results were really good, considering my crappy Photoshop skills. Just for fun I ran the RAW converter on a couple of images I shot using about 2 stops of overexposure. I was able to reduce the exposure in the converter and bring out a nice blue sky/white cloud image where the JPEG only shows a white sky.

To sum up a long story, the XTi will underexpose but it does it to squeeze as much of the contrast range as possible into the image. If you shoot in RAW mode, you can do a double-RAW conversion and recover both the shadow and highlight info. Unfortunately if you shoot in JPEG mode they just look dark.

I’ll try to post a few images tonight if anyone is interested.

 

[Gene Moore]

another footnote on infinity focusing for Canon

Manual focusing that is.....

This also relates to other threads where night focusing is an issue. Some of the recommendations include going to manual focus, but I stated I could seldom get an accurate focus with some lenses. Now I believe I know the reason why and I'll put it to those interested in this subject. I have in hand a copy of the new 2007 Canon EOS system book that lists all the available products and lenses. In the lens section there is a breakout of particular lens features like circular aperture, inner and rear focusing, AF stop feature and so on....there are many. Of special interest is a feature called "Full-Time Manual Focusing" or FT-M as listed under each lens. Now, here is the kicker; some of my lenses and some I've used belonging to chase partners do correctly manual focus, some do not. Looking at the list the ones I could not use to get a good manual infinity focus did not have the FT-M feature. Example, my EF 50mm f1.8 lens will not manually focus well nor would my kit lens EF 18-55 f 3.5-5.6 (that I no longer have). Neither had the FT-M feature, but my EF 85 f 1.8 USM will and it does have FT-M. I could list more lenses but you get the idea. Why is this so?? Canon states "these lenses can manually tweak focus without switching out of AF mode." That is, within the lens I think there is a better coupling design with the autofocus system. Anyway, it's my opinion when buying a Canon lens that may be used to manual focus this feature should be included. All the L lenses have this feature and most of the high end lenses with IS also include this feature. Hope this helps those of us that stumble around in the night with tripods.

Gene Moore