lu_yin

I have been using 70-200/4 for 2 years on a 10D body. Until last

week, I never had much problem with it.

 

Recently, I was shooing a big sign outside my house about 15 yards

aways on a bright day. The setting was like 100 ISO, F4, 1/1200 sec.

The shooting was in Av mode, and the center autofucus point was

selected. The sign has white background, big blue letters on it. For

some reason, the camera consistently (I took 20 photos) focused 2 feet

behind the sign.

 

I got scared. So I took many more test shots that I had not done

before. I took pictures of rulers and stacked books in the room on a

tripod. All photos showed slight back focus.

 

What was curious to me was that I never had or noticed this problem

before. So I looked at my old photos taken with the same camera and

lens and noticed that most of the pictures had right focus.

 

Then I took the camera out this weekend to the Moody Garden near

Houston. I took about 100 shots with the lens. Most of the pictures

were taken with the following settings: 400 ISO, Av at F4, 1/160 Sec,

flash on, mounted on a monopod. I would say that 90% of the photos

were in focus.

 

So here is my question: what is wrong with the lens? Or my technique?

I try to focus with the center focus square (so 2 focusing sensors?)

on contrasty areas (the eyes for example).

 

What else can I do with my technique? Or the lens? Should I send it

to Canon for repair/check up?

 

Thank you.

 

Lu

You guys probably understand MTF better than I do. I am just curious as how accurate those measures really are.

 

Canon's own MTF charts are so optimistic. The photodo ratings, which are supposedly baesd on real lens measurements, tell different stories.

 

Sigma's MTF charts, on the other hand, are just confusing. For instance, I own both Sigma 24-70/2.8 zoom and 15/2.8 fisheye. From what I can see on Sigma's charts, 24-70 is much sharper across the whole lens with better contract wide open. I never performed MTF measurements, but I know from my experience that 15/2.8 is way sharper and contrasty than the zoom, as prime are generally better than zoom. Did Sigma do something funny with their MTF charts?

 

Finally, is there any web site that uses tools such as DXO and large sample of lenses to making meaninful measurements? There are so many rumors on the web. These opinions about lenses are generally unsupported statement based adversely selected users. Either by people who suffered from bad samples and bash the lens or from those whose sunk in costs provide much pride to praise the lens.

 

I am very interested in 30/1.4 for it's wide aperture. However, I must have some good reason to justify getting it on top of a Canon 35/2. It's quiet a high price to pay for a DC lens made by sigma. From my own experience, 35/2 is very sharp and contrasty. I am skeptical that 30/1.4 can be that much better.

 

Lu

Well, try to stay away from Cokin filters if you can. Their filters are built with resin, which is so soft that you will end up replacing filters quiet often. So higher cost to you in the long run.

 

As people suggested, 2 filters (58 and 77) with stepdown rings should be a good setup.

Cokin system is probably the best for GND filters. However, they are actually very expensive in the long run. Cokin filters are make of resinm, which is really soft and scratches easily. Get glass filters. Save your money in the long run.

This subject seems to be beaten to death in the dpreview forum...

 

Here is what I learned.

 

Lens like 50/1.8 works, but 50/1.4, or 28-135/IS won't work, as they have different coatings. I don't know what other lenses would work.

 

The exposure for IR picture would be long.

1. The IR filter w/i the 10D blocks light really well...

2. You need small aperture to get enough DOF to ensure that you are focusing on the wrong subject.

 

For landscape shots in a sunny day, my typical setting is: 100 ISO, f/11, 25 sec.

 

The good thing is that you have instant (almost) feedback with the histogram.

 

Good luck!

 

Lu<div></div>

I think Helix has more professional and friendlier staffs than Central's in camera/lens departments. Their price is almost always higher than BH/Adorama (but 10D seems to have the same $1499 price tag everywhere), and you would have to pay sales tax. In addition, they ususally don't have the camera/lens that you want, and they would tell you to wait a couple of weeks, which is slower than ordering it from BH. But you got to play with the camera first in you buy it in the store.

 

For 2 weeks, it is enough time to order it from BH/Adorama.

 

Good luck!

85/1.8 if that's your only lens for portrature. 85 after 1.6x is ideal for tight face shots. 50 after 1.6x is good for shoulder shots. It's usually easier to move back a few steps than cropping photos.

Polarizer won't work with that kind of wide angle.

Yep, * works as FE lock in manual mode. I had to use that on my 10D as well when I want to lock flash and exposure separately.

20x30 from 10D actually looks pretty nice after enlargement and sharpening. The print won't look ultra sharp with magnifying glass, but quiet good in normal viewing distance Scanned 35mm are OK up to 8x10, but would start to look really grainy when you printer bigger sizes.

If you don't mind de-fish, get sigma 15mm fisheye. It's even wider than 14mm rectlinear. Around $320.

Buy now.

 

I had similar experience.

 

The truth is the saving you will have on 10D after price won't be that big a deal compared to the vacation that you will have.

 

Buy the camera now and spend sometime to learn the camera before the vacation.

 

Finally, it's unlike that they will drop the price much. They have rebel covering the lower end already.

Shooting color then convert in photoshop is actually better.

 

Remember the old days when you have to use color filters (red was my favorite)? Now you can just use channel mixer to get the same result.

 

P&S cameras may be able to produce BW pics, but they are done by desaturation (ctr-shift-u in photoshop). But images produced that way are usually flat.

your combo is really not that heavy. A bogen 484 head should be more than enough.

 

Make sure you have ball head though. While you can move the monopod, you often have to anchor monopod in a certain way to ensure stability. When you do that, you have no freedom at all and a ball head becomes necessary.

 

It would be a good investment as I think you would like ball head on your tripod as well.

 

Good luck!

they are right: 70-200/2.8 for close up portrait, 17-40 for interior/group/whole body shots.

The truth is that optical quality alone does not worth $800 unless you are unbending about image quality. Canon produces much better contrast.

 

But in the long run, I think Canon might be better. The build quality of Sigma makes you wonder sometimes whether you can trust it. I had mine recently sent to repair shop and it takes ever to get it fixed.

 

In addition, 24-70 has additional flaws. The operation is pretty weird; switching between focusing mode requires using a clutch, which is very annoying. And it is quiet noisy even for Sigma's standard.

 

The last thing is that the 82mm filter size would really makes a big difference in filter price.

 

Havingin said all of that, I thought the $800 difference was enough of a difference for me to choose the Sigma, mainly because I don't use 24-70 range all that much. For 70-200, I didn't even think twice before choosing Canon L.

No, unless you are 100% steady with monopod.

You probably don't need 17-40L is you are only shooting landscape at f/8. At that aperture, pretty much all the lens are the same. Just remember to carry a tripod.

 

If you enjoy macro, like that bug picture, getting a decent telephone zoom is probably better for you. As suggested, 70-200/4L is a good choice.

 

And also consider 15/2.8 fisheye. It's a much wider lens (actually wider than 14mm rectlinear).

There are two answers to "digital spoils" issue.

 

1. Is the future going to be just digital? While many people here would not agree, I think so. Digital is the way to go. It just makes life simpler. If that then case, digital is the norm and what is the point keeping all the skills that is reserved to film. But what is the skills that is only required by film other than working in the dark room?

 

2. Naturally, it leads to my second point. It's up to you to make sure that you do the right things (framing, exposure, etc). There are tons of trigger happy people out there with DSLR who shoot thousands of frames will very few keeprs. There are also pros who shoot seriously and have many more keepers (but pros waste a lot of frames too, even when film was the only medium). So you have to make sure that you learn from digital cameras, not just to rely on luck and number.

 

DSLRs are great for learning. For any kind of learning, feedback is one of the most important element. Instant feedback makes learning photography much easier.

 

Having said all that, there are plenty of reasons to keep your EOS 1 over 10D. For one thing, unless you spend a fortune to get 1Ds, you would suffer at the wide end. Also, 10D is an amature body. In term pure camera functionality, it is no match from EOS 1/3. And there are other things that makes EOS 1 superior.

 

I used to use film camera. That was why I stopped shooting: all the trouble with carrying film, developing, keep negatives, scanning, etc. Too much trouble. 10D help me discover photography again. Don't underestimate the power of convenience.

William, what's that "you need to rethinking" stuff?

 

Do you own any wide angle lenses? Just look at them. They can't support that big a sensor. If you look at Canon 14mm or 15mm, you will see that there is actually a 2x3 ratio frame inside the lens.

 

If you don't believe in that, tape a cricle on your lens see what happens.

300f4 with 1.4x will be fairly close to 400/5.6 in sharpness, but not as good. 1.4x with 400/5.6 will disable AF on 10D for a good reason: it's too dim to focus accurately.It's probably a goodf idea to have 300/4 as IS will be available, and it weight about the same as 400/5.6.

I really don't know why people buy 50mm macro. Unless you are photographing non moving subjects, you never get close enough. Perhaps it allows you handhold better b/c of shorter focal lens? It is really not a macro lens: it goes to 1:2 and they you have spend another $200 to get extention tube to get 1:1. If you want 1:1 macro, 50mm Sigma is a better choice.

 

But then, if you really want a macro, 100mm USM is a better choice. It gives you much more distance to work with and it is 1:1 (don't need extention here).

 

If you just need a normal lens, 50/1.4 is great. It is better than 50/1.8. But honest, I don't' think you will see much difference in terms of optical quality. 50/1.4 gives better boken, faster, better build, and has USM. But it's also 4 times as expensive.

that combo should be very good. At 4x6 you should be able to produce good images even if there are some minor blur or high ISO level because you down sample so much.

 

Perhaps you should play with the lens in different setting (aperture, ISO, etc) to see if there is any human error or other issues (such as focusing problem, though much rarer than what people rumored over the Internet).

If you are testing the lens in store, it is unlikely that you will be able to really test it as extensively as others who own the lens: they spent hours shooting MTF charts and difficult situations.

 

What you do want to test is the operation and build quality of these lenses. See if you like them in your hand. Perhaps how fast they focus.

I just tried it with 70-200/2.8 by using DOF preview button to switch between f/4 and f/2.8. At all three focal lengths, the DOF diffences seem small. It difference is most noticeable at 200mm in the viewfinder. It might be different with actual picture.