SX60 auto focus problem at high zoom

[ojreichman]

At zoom levels approaching max. optical and into digital zoom the camera fails to auto-focus (but does so at zooms below 50X).  I’ve tried many of the permutations of focus settings, and read earlier posts relating to similar issues, but have not found a solution.  I have been working with plenty of light (ISO 200, shutter speed 1/250 and up, and within the aperture range of the camera).  

Suggestions?

Thanks...

[Waddizzle]

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@ojreichman wrote:

At zoom levels approaching max. optical and into digital zoom the camera fails to auto-focus (but does so at zooms below 50X).  I’ve tried many of the permutations of focus settings, and read earlier posts relating to similar issues, but have not found a solution.  I have been working with plenty of light (ISO 200, shutter speed 1/250 and up, and within the aperture range of the camera).  

Suggestions?

Thanks...

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What are you trying to focus on?  At the very high zoom ratios, you probably need to use a tripod to steady the camera, so that it can lock onto a subject that is “under” the AF sensor’s coverage.  Make sure that you focus on an area with high contrast.

[ojreichman]

I was using a monopod while leaning against a door jam, so it seems quite stable.  I was shooting skiers, small groups of people, against a snow background.  It also tried focusing on structures (e.g., sheds, etc.) that filled more of the focusing frame, with the same results.

[John_]

What mode are you shooting in? I have the SX50HS, very similar to yours. At high zoom, I use Program mode, a tripod, and remote shutter switch, wired or wireless. Equally important I also use Flexizone focus which allows me to shift the focus frame to an area on the subject with enough contrast/detail to achieve good focus.

[Debra1]

Can you post a photo of what you are trying to focus on, even if it is blurry? It might help to see the what you are trying to capture.

[ojreichman]

I took many photos under various conditions but here are a few that were near/ar full optical zoom.

[Waddizzle]

All of those shsts are uniformly OOF, out of focus, which means the entire frame is equally OOF.  This usually points to either camera shake, or too slow of a shutter speed.  Your issue seems to be a combination of both.

I do not think your monopod leaning against a structure is sufficiently steady.  I know it does not work for me when I try to take photos of the Moon with my full frame DSLR at 600mm.  With the smaller sensor in the SX60, combined with a longer focal length, the problem of camera shake becomes even more acute. You really need a tripod at super telephoto focal lengths.

You said your shutter speed is 1/250, or faster.  That is too slow by at least four stops when you are shooting at the maximum equivalent focal length of 1300mm, if not much higher.  Let me explain.  

The rule of thumb with a full frame sensor DSLR for setting a minimum shutter speed says to set it at 1/FL, where FL equals the equivalent focal 35mm focal length of the lens being used.  With a smaller image sensor, you have to multiply that by the Crop Factor.  Your camera has a crop factor that falls somewhere between 5 and 6.  So, let’’s call it 5, for argument’s sake.  

Crop Factor is the the multiplier you use to estimate what the equivalent 35mm focal length would be.  The actual lens has focal length that ranges from 3.8 -247mm.  Your camera’s sensor creates an equivalent focal range of 21-1365mm, which is HUGE.

When the actual focal length is 247mm, the 35mm equivalent focal length is 1365, which means your minimum shutter speed needs to be at least 1/1250, if not faster.  Of course, IS, Image Stablization, can help bring that number down.  But, IS becomes less effective as your focal length increases.  In fact, IS really should be turned OFF when you use a tripod.

I think the cure is a steadier platform, and a much faster shutter speed.  You need to be at least 1/1000, even if you use a tripod.  If you do not have a remote shutter switch, then use the camera’s shutter 10 second delay timer.  

[ojreichman]

Very helpful information.  I thought I knew something about photography, but have never been in the land of 65X before.  Thank you.

I tried 1/1000 and even 1/2000, with little effect, but I understand your point.  I’m traveling, without a tripod, but will follow up on that.  Something that interested me is that the camera’s behavior was the same through all of this.  Depressing the shutter button caused it to focus through the subject and beyond, then back up a bit but out of focus.  Sometimes the yellow box would appear, but sometimes not.

But her’s sometinhg interesting.  I had a polarizer filter on.  I took it off and the problem disappeared, even up into the digital zoom (maybe that part is not a surprise if it is just sampling the 65X image).  I know polarizers knock the light down a couple of stops, but I’m surprized by this result.  Is there something about polarized light, either as part of the polarization or some side effect, or something about the way sensors deal with polarized light, that might cause this ?

Thanks again...

[Debra1]

That was a good idea to test the camera by shooting without the polarizer.

I use my SX60 hand held at maximum optical zoom frequently because I often shoot birds and wildlife, and your hand held images should not be that blurry. It sounds like your filter may have been the culprit. Perhaps it reduced the contrast so much that it was too dark for the settings you selected and the camera couldn't figure out what to focus on? Digital cameras seem to want to focus where there is the greatest contrast. I wonder if another contributing factor might have been very cold weather if the camera got really cold; perhaps it slowed the shutter a little? (just guessing)

I can't offer much help with technical settings and am still exploring how to get the best images from my own SX60 but I have had pretty good results with it as well as my SX40 and SX230. When my experimental settings get too far off and my photos don't come out well, I test the camera by putting all settings back to Default (select "Reset All") and I take a few photos of the same or similar subject with the camera on "Auto" to test. If the image turns out with good tone and detail, then at least I know the problem lies with the adjustments I made and not the camera. Attached is a shot I took with the SX60. Hope some of this might help.

[ojreichman]

Waddizzle - any thoughts about the removal of the polarizer affecting the focus, other than just (just?) increasing the light a couple of stops?

Thanks,  Jim