D30/50mm f1.4 close focus problem

[walkerd]

My D30 is not close focusing correctly. I received my D30 last week along with a 50mm F1.4 and 28-135 IS. After shooting some aquarium pics at Ripleys Aquarium in Gatlinburg TN, I noticed that almost all the pics were out of focus. All the pics were shot in manual mode with manual focus and with the 50mm at between f1.4 and F2.0. Shutter speeds were shorter than 1/60 - most at about 1/125. I decided to do my own test on a tripod with the 50mm. I set up an 18" ruler and manually focused on the "35" marking. As you can see at http://64.85.6.147/focusproblem.htm (600k), the focus appears to be on the "33" mark. I thought I had introduced some error so I repeated this test very carefully over and over and always got the same result. I was careful not to hit the focus stop on the 50mm but to leave a little room. I also used a remote switch. The image in the viewfinder always appears correctly focused on the"35".

Anyone care to enlighten me as to what is happening? It appears I have something wrong with the D30 or the 50mm or both.

After spending over $3000, I am very disappointed with this performance.

Doug Walker

[JCDoss]

I hope you enjoyed the Aquarium... It will be one of my first stops when I get my D30.

Re: Your experiment. Have you tried selecting only the center AF point and autofocusing on the 35? If the AF module also focuses on the 33 instead of the 35, then I'd be confident that the AF module needs recalibrated by Canon. If the AF module focuses on the 35, then I'd be suspicious that you're eyes are focusing through the lens due to lack of a good ground glass focusing screen.

JCDoss

[walkerd]

Ripley's Gatlinburg aquarium is must see. It's very crowded this time of year however and is a little difficult to get good photos.

For the test shots, I did try using AF with the center AF point but got the same results. I also ran the test using my 28-135 IS and those results are here:
http://64.85.6.147/focusproblem2.htm
The focus point on that test was the "3" in "30" using manual focus in full manual exposure mode as in the previous tests. As you can see, it looks ok.

I also shot a Canon lens cap with the 50mm wide open focusing on the word "Ultrasonic". That pic showed a large amount of aberration around "Ultrasonic" - much more than I would expect. The actual focus point with the 50mm appears to be somewhat closer than what you see when looking through the viewfinder. What could cause that (with one lens and not another)?

It looks like there is a problem with the 50mm. Either my 50mm is bad or the D30/50mm design is flawed. I really don't understand why the viewfinder appears sharp with both lenses but only the 50mm produces a focus shift on the final image.

I hope that Chuck Westfall would jump in here and shed some light on what is happening.

I have just a couple days left on my return period for the 50mm at B&H, so I need to figure out just where the problem is.

Doug Walker

[JCDoss]

Doug,

First, Chuck Westfall doesn't frequent this forum, so it's awfully unlikely he'll come here to answer your question! :-) He does appear at www.robgalbraith.com with some regularity, so I'd recommend re-posting your situation with links to your images there.

Although it looks like the 28-135IS did a better job of hitting the target, the zoom is sufficiently slower to allow a significantly greater depth of field. I assume you shot at 50mm, where the lens has a max aperture of probably f/4 (versus the f/1.4 and f/2 of the 50mm prime). Therefore, aperture and depth of field may be playing a role here... perhaps the DOF was "wide enough" to have included the intended focus point taken with the zoom, but wasn't "wide enough" to hit the target with the 50/1.4. Not only that, but the two photos appear to have been taken at different distances, which will further complicate issues involving DOF. (I don't know, I'm just spouting some ideas.)

My suggestion would be to exchange the 50/1.4 lens (since your window to do so is shrinking). Repeat your tests, and if you have the same problem, start thinking about having your AF module calibrated. I've also read that minute misalignment of the mirror (upon which the AF module is dependant) may cause similar problems, and these problems are not all that uncommon in film SLRs.

And, certainly, post your story at www.robgalbraith.com and hope that Chuck responds. If he doesn't, there's enough collective wisdom and collective experinece to give you some better ideas than I may have.

JCDoss

PS: Do you have a link to your aquarium pics? I live in Knoxville, and I'm *purposely* holding off my trip until after I get my D30! I know I'll want to cry if I go there without it.

[walkerd]

JCdoss,

No I don't yet have a link to the pics as I just shot them last night and didn't get home until about 10pm. I was so dismayed as to the focus problem, I stayed up until 3am testing. Only one or two of the entire batch is worth saving. I live in Sevierville and have a season pass so another trip is pretty easy.

Yes, even though the apertures were different (1.4 vs 4) for the test photos and the distance was also different, the main issue is still valid - the focus point, as viewed through the viewfinder, for the 50mm is significantly different than the 28-135 IS. So significant that the resulting image shows that point completely out of focus.

I guess your suggestion to return it for another sample is the best course of action. I just have a hard time believing that Canon's quality control is that lacking. I spent a lot of time deciding whether to spend 4 times the price for the 50mm 1.4 over the 1.8 and, upon urging from others, finally gave in to the 1.4. With the very shallow depth of field of the 50 1.4 there could be an alignment problem with the sensor/mirror/prism in the D30 that isn't seen in normal circumstances. I just feel like this is the beginning of a search for a needle in a haystack.

Most closeup work is done in somewhat controlled environments with very small aperatures. In those cases, this problem would not be seen (the depth of field would be greater than the misalignment). Aquarium shoots look best with ambient light (at least to me) and small aperture macro lenses really don't work well.

Doug Walker

[JCDoss]

Doug,

I just read and replied to your post at www.robgalbraith.com. I think the results of the 50/1.8 suggest a misalignment problem, possibly with the mirror. These problems are apparently not uncommon with film cameras and are easy to fix.

Where did you get your camera, btw? Did you get yours locally? What photo shop do you use locally?

JCDoss

[walkerd]

I bought the camera at B&H Photo by mail order and they only offer a 7 day return window for digital equipment so I'll have to find a Canon repair center and send it in. This is unfortunate since one of the reasons I purchased it now is for a trip to CA in August to see a grandchild I have never seen before. I bought the 50mm F1.4 in hopes of getting some ambient light photos of the newest member of our family.

I have no experience with Canon's service but I would expect that it would take 4-6 weeks to get tweaked.

I sometimes use Thompson Photo locally but their price for the D30 was just too high.

Doug Walker

[WebChanter]

Hiya Doug.

I just got my D30 and haven't much experience with it yet, but the problem you saw with distortion around the word "Ultrasonic" just made me think "jpeg". I hate the distortion jpeg compression causes, especially around hard edges. Any chance you were looking at a jpg pic?

WebChanter :)

[walkerd]

If you are talking about jpeg "artifacts", no it is not that. I'm actually having additional problems with the autofocus system now as it hunts so bad in bright daylight that I have to go into manual mode to get a focus lock. It does this about half the time now with the 28-135 IS and my Tokina 17mm ATX Pro.

I'll be sending it in for a complete recalibration as soon as I call Canon.

Doug Walker