S90 focus issues?

[skynscuba]

I notice that my S90 often has trouble focusing correctly in moderately close macro shots. I got it just before a dive trip, and initially thought that my focus problem was solely due to the difficulty of doing a "half press" of the shutter button in the Canon housing. However, I have the same issue with just the camera, sitting here at my computer.

If I repeatedly do the half-press focus, while backing up from minimum focus range, I'll find a spot-- sometimes -- where the focus is totally fuzzy. Press again without moving the camera, and it is usually fuzzy again, but might be just fine. When it mis-focuses, it seems to focus at the maximum Macro distance of ~50cm/20".

Sitting at my desk, focusing on the Tab key, this doesn't happen always, or half of the time, or even 1/10th, but it definitely happens too often.

I know dogdrjohn posted about having some focus issues underwater. Anyone else? Any one but me notice that on the surface?

 

[bsppc]

I had the same soft focus issues on a dive trip to Cozumel last month. I can also relate to what you are saying, as I have done the same focus testing at the house and had mixed results.

In my experience shifting between macro and standard cleared up the focus problems. In other words, if I am in macro and get a soft focus, just switching to normal brings the image into focus, and the same works in reverse when focus is soft in normal and I switch to macro.

I thought some of this was lack of light under water, but the problem still persisted even when using a focus light .

I think that changing the setting to spot focus helps the camera gain a good hard focus as well.

Bill

 

[Nemrod]

1. Use Center focus setting.

2. Use the half press feature with the magnified focus window. If the yellow box comes up instead of the magnified focus window, you ain't gonna be in focus.

2.5. Turn off all the auto functions, safety focus functions, stupid focus light etc.

3. The S90 focuses like all P&S cameras, better in bright light and with contrasty subjects.

3.5. Use a strong focus light like the one my D2000 strobes have.

3.7.5. Do not use the A (Auto) setting

4. Wish for the day that there are fully manual everything cameras again with simply a digital sensor--problems are all suddenly solved.

N

 

[skynscuba]

I do all of that, except I can not find "spot focus" as a choice on this camera. There is such a choice for metering (evaluative, center weighted, spot), but the only focus settings I see are "face" and "center," where "center" allows a choice of frame size, "normal" or "small."

 

[Nemrod]

I do all of that, except I can not find "spot focus" as a choice on this camera. There is such a choice for metering (evaluative, center weighted, spot), but the only focus settings I see are "face" and "center," where "center" allows a choice of frame size, "normal" or "small."

LOL, I was confusing something, too many things going on, yes, pretty please turn off the Face Detect and go to Center. The choice is under the Menu button.

Sorry about that.

N

 

[skynscuba]

Okay, I got a replacement S90 (have both right now, gonna send one back) and .... pretty much the same result on erratic macro focus. Usually okay, but off often enough to be irritating. I had thought perhaps that the original one, which has been dropped, was out of kilter from that, but apparently not.

More light (LED flashlight from a foot away) helps some, but it isn't exactly dim at my desk without the flash -- F2.0 / ISO100 / 1/80th second for correct exposure. Oddly, just having the light from my monitor (room lights off) works pretty reliably, maybe because of more contrast, but even on a subject with almost no contrast.

Gotta also add that the manual focus seems not as well implemented as it might be. The acuity in the enlarged focus window doesn't change very quickly as distance is adjusted -- it is only when you do a half-press of the shutter that you can see how in/out of focus the picture will be.

The replacement S90 also has one bad pixel in the sensor.

 

[Puffer Fish]

Okay, I got a replacement S90 (have both right now, gonna send one back) and .... pretty much the same result on erratic macro focus. Usually okay, but off often enough to be irritating. I had thought perhaps that the original one, which has been dropped, was out of kilter from that, but apparently not.

More light (LED flashlight from a foot away) helps some, but it isn't exactly dim at my desk without the flash -- F2.0 / ISO100 / 1/80th second for correct exposure. Oddly, just having the light from my monitor (room lights off) works pretty reliably, maybe because of more contrast, but even on a subject with almost no contrast.

Gotta also add that the manual focus seems not as well implemented as it might be. The acuity in the enlarged focus window doesn't change very quickly as distance is adjusted -- it is only when you do a half-press of the shutter that you can see how in/out of focus the picture will be.

The replacement S90 also has one bad pixel in the sensor.

Yup, mine (both of them) do the same thing. It will do a focus and be completely blurry. How bright it is has a major effect on this, but even when bright it can do it.

It is terrible with any add on lens.

I've taken to using the magnify and moving the camera around to get the correct focus. But if one cannot get to the half depressed point...most images will be out of focus.

My guess is there is some design flaw in the focus, as getting a focus lock on nothing should not happen.

As I can do the half depressed, correcting for it is not too bad.

Manual focus might be one option and use the ring.

 

[Nemrod]

What distance and what focal length are you shooting at?

Also what exposure mode etc. I want to try and duplicate your problems. I cannot get my camera NOT to focus so I am obviously not doing what you guys are doing or seeing for whatever reason?

I shot this sequence for Scott on my dining room table:

28mm:

35mm:

85mm:

105mm:

50mm:

I got good focus lock each time but I do notice that if I get very close then reliable focus is not so quick. Is it possible you are to close?

Way back I had a focus wand for my Nikonos III. I preset focus and then placed the object to be photographed between or at the tip of the wand.

N

 

[slowhands]

I notice that my S90 often has trouble focusing correctly in moderately close macro shots. I got it just before a dive trip, and initially thought that my focus problem was solely due to the difficulty of doing a "half press" of the shutter button in the Canon housing. However, I have the same issue with just the camera, sitting here at my computer.

If I repeatedly do the half-press focus, while backing up from minimum focus range, I'll find a spot-- sometimes -- where the focus is totally fuzzy. Press again without moving the camera, and it is usually fuzzy again, but might be just fine. When it mis-focuses, it seems to focus at the maximum Macro distance of ~50cm/20".

I don't have an S90, I played with one for a week and returned it in favor of the G11. But I tried a lot of close focus when I had it. I think it does best on close focus in the Wide setting. Tele macro did not work for me. In other words, when in Macro mode, zoom to the widest setting. That worked best for me. I think if focus is critical on a subject, I would use center focus on that area and recompose. Also, I needed plenty of light, so I would expect to need a focus light in the water.

Here is what the specs from Canon say about focus range:

Auto: 2.0 in./5cm-infinity (W), 12 in./30 cm-infinity (T)
Normal: 1.6 ft.-infinity/50cm-infinity
Macro: 2.0 in.-1.6 ft./5-50cm (W)​

Notice Canon puts W wide by the macro range. I think they are implicitly saying it works better at wide zoom, or maybe only there. But I did not see that in the manual, so it's my guess. Just what I observed in some evaluation testing here, if that helps. I don't profess to be an expert, and I am not knocking the camera. I'm just saying, this is the way I found it to work best for me in my brief testing.

In fairness, the camera was amazing in being able to do all it could do. Close focus to 2 inches, fantastic. The image quality was great.

 

[dhaas]

Amigos,

Virtually ALL Canon P&S (point and shoot) models including Canon G10, G11 focus CLOSEST when at the wide position. I don't know if this is due to the zoom lens or what.

The MINIMUM focus that can be achieved when zoomed and in MACRO mode is clearly stated in every Canon manual. Zooming to the maximum (i.e. 105mm equivalent focal length) is a bit too far away in my opinion.

In real world shooting UW where you aren't going to get any LIVE critter let you get that close, plus get your darn strobe(s) in position to light something 2" or so in front of your camera. So practice is necessary.....

I have found once I hit the MACRO button zooming 1/2 - 2/3 of the range (80mm equivalent max) keeps me back far enough and also allows the strobes to be effective.

Too many shooters cram their strobe in too close and then blow out their subjects when shooting macro anyway.....

Plus my Ikelite AF35 strobe's sensor works best for TTL feedback between 1' - 4' from your subject.

So pull out your camera, put it in MACRO mode and ZOOM to various focal lengths and practice going closer, closer, closer until you can't get a GREEN focus confirmation block.

YMMV

dhaas
David Haas Underwater Photography