Q's for D30 users!

[Jorge]

I have a few Q’s about the D30:

Q1: Is it true that D30 can’t auto focus with lenses that have max aperture slower than 5.6 (I have an old Cosina 28-300 mm that has max aperture 6.3 @ 300)?

Q2: I’ve read that the magnification available when reviewing shots on the LCD is not good enough for determining whether a shot is in focus or not. Is this really true? And is it possible to check if exposure is correct on the LCD?

Merry Christmas!

[Pekka]

Jorge wrote:
I have a few Q’s about the D30:

Q1: Is it true that D30 can’t auto focus with lenses that have max aperture slower than 5.6 (I have an old Cosina 28-300 mm that has max aperture 6.3 @ 300)?


Hi Jorge,

As I recall the focus motor sensitivity limit is f 8. E.g. 100-400 works with 1.4X extender but not with 2x. Someone please correct me if I'm wrong.

Q2: I’ve read that the magnification available when reviewing shots on the LCD is not good enough for determining whether a shot is in focus or not. Is this really true?

You can not see if it is tack sharp or not, but it is sharp enough that you can determine the DoF and what was the focus point, when zoomed in.

And is it possible to check if exposure is correct on the LCD?

Yes, looking at the image plus examining and understanding the histogram display you can determine if exposure is what you need it to be. The LCD shows shadow detail a bit "too" clearly, so on computer CRT you may get a different impression. But histogram does not lie.

[redbutt]

As Pekka noted, the LCD is just fine for determining if your shot is good. The histogram is a great asset to learn how to read.

[jmublueduck]

yeah, pekka's wrong (sorry bro)... autofocus does NOT work well, if at all if you have a lens with a max aperature of > f/5.6. this is in Canon's documentation somewhere.

BUT if you're good w/ manual focusing, the lens should work if you can use it w/ an EF mount. Then again, if @ 300mm the max is f/6.3, that's less than a 1/2 stop difference over f/5.6, so who knows? try it & let us know!

[jonsimpson]

are you guys refering to NON canon lenses?

[rickm]

jonsimpson wrote:
are you guys refering to NON canon lenses?
No, any lens. The autofocus needs a certain amount of light to get transmitted to work correctly. In the case of the D30/60, the lens can't be slower than F5.6. In the 1D, it will work with one as slow as F8.

As for checking focus on the screen... I have perfect vision and can see enough contrast to think it's close but if I then had to hand my CF card to a lab for a 20x30, I'd be real nervous that I got it. IMO, if you need to manual focus, you better stop down and use the depth of field to help.

[robertwgross]

I shoot the D60, which is similar. I would say that if I blunder and shoot something _bad_ in terms of focus or exposure, then that should be readily visible on the LCD, so I can delete it and continue.

It is sometimes hard to tell whether the shot is _perfect_ or _good_, just based on the LCD view. The histogram should tell me if it is going to have major adjustments necessary in the computer. If the histogram suggests that it is _bad_, then I delete it and continue.

Remember: "There is a fool who can overcome any foolproof scheme."

---Bob Gross---

[jonsimpson]

I posted this in another thread.....but I think it is more valid on this thread........

I'm so frustrated with my D30 autofocus.

The most common shot for $ I do is a 3/4 shot.

I'm usually 8-9 meters away. Shooting with my 70-200 f4 Canon L lense. Usually shooting at 150-200 mm (which is even higher due to D30), try to shoot with my shutter speed faster than lense MM, at a F stop between 5.6-8.

The below image is par for the course. I have the center focus point selected. Camera on tripod. I tilt up and put the point on her eyes, hold shutter 1/2 down to get autofocus, then holding it down reframe and shoot.

The below pic is: 149mm, 5.37m , 1/320/f7.1, ISO 400, AF on one shot. TV mode. Raw.

I cropped the image for quicker download..but to my eye the focus is just hehind her head. Look at the letters on the wall. And her face is soft. Aaaaaaaaaaaaaargh. Pretty consistently like this.

Have had the camera for a year. I have the latest firmware. Arrrrrrrrrrrrrgh.

HELP
http://jonsimpson.com/post/aaargh.jpg

[oops]

Jon, Hi.

It would seem the focus point is, indeed, behind your subject. This brings back the G1 focus horrors of a little more than 18 months ago when hapless new G1 owners clogged almost every forum with focus problems.

Those threads have long since expired but the doubts about Canon's choice of focus technology for their different camera models just seems to rival even the Energizer Bunny. It would seem the D30 and perhaps the D60 are not immune to cost saving focusing technology decisions.

Michael Reichmann, http://www.luminous-landscape.com, was a very avid promoter of the D30 early on and later admitted the camera has a disappointing, low grade focusing system. But, those of us already fighting the D30 focus snarl had already come to this conclusion by experience.

We are, regardless, married to whatever problems exist with our cameras and there may be 'walk around' solutions. We must first admit there may be a problem then share what has worked for us. :) I am, if it helps, as frustrated as you are with focus irregularities.

The problem with the G1 focus was best addressed with contrast, not f-stop. It seemed the G1 would 'find' the object in the frame with the best contrast and make that its focus point regardless of where the camera was pointed. This was both proven and dis-proven several times over the early months. My personal experiments with my G1 and D30 have shown both contrast and f-stop are important with contrast taking top priority.

In your example, the wall behind your subject would be very tempting to a camera looking for contrast. Does the D30/D60 look for contrast? Beats me. And yes, you said you had center focus point selected. So do I almost 100% of the time and my images are no different from yours. Frustrating, indeed!

To top it all off, some of our images are magnificent regardless of tripods, lenses, f-stops, or lunar cycles, right? So much for scientific hypothesis, controlled experiments, and Nobel results!

I hope I have helped rather than complicated your frustration. Try some experiments using contrast as the governing factor for focal plane and let us know how (if) it makes a difference for you.

Chris

[Motorsports Photo]

Jorge wrote:
I have a few Q’s about the D30:

Q1: Is it true that D30 can’t auto focus with lenses that have max aperture slower than 5.6 (I have an old Cosina 28-300 mm that has max aperture 6.3 @ 300)?


The D30 has trouble focusing in low light situations. If you are "shooting in the dark" the center sensor is your best bet. It sees vertical and horizontal while the two outside sensors only see horizontal. (I think I remember that correctly)


Q2: I’ve read that the magnification available when reviewing shots on the LCD is not good enough for determining whether a shot is in focus or not. Is this really true? And is it possible to check if exposure is correct on the LCD?

Lets face it, that tiny screen just isn't big enough to tell focus sharpness. You can do a zoom and tell a little better if the focus is good. Its easier to take a few different shots and keep the best one. The best feature of the LCD is to view the histogram, and to see blown out highlights.

-PS
Strasburg, oHIo