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-   -   HELP! 70-300 af (http://e-group.uk.net/forum/showthread.php?t=20754)

Barkly 28th May 2012 08:43 AM

70-300 af
 
I seem to be having problems with getting sharp images at distance with the 70-300mm. I wear graduated glasses and need to use AF.

Any suggestions?

Ian 28th May 2012 08:59 AM

Re: 70-300 af
 
Can you provide some examples? How are you steadying the camera? 300mm is a fairly extreme telephoto setting so you will need a suitably fast shutter speed, even with IS enabled.

Ian

Barkly 28th May 2012 09:07 AM

Re: 70-300 af
 
Not really steadying it - should I use a tripod?.

EXIF is there - cropped of course.

http://i59.photobucket.com/albums/g2...y27SCCBoat.jpg

http://i59.photobucket.com/albums/g2...onalMuseum.jpg

Howi 28th May 2012 09:37 AM

Re: 70-300 af
 
Quote:

Originally Posted by Barkly (Post 168353)
I seem to be having problems with getting sharp images at distance with the 70-300mm. I wear graduated glasses and need to use AF.

Any suggestions?

Hi there, you need to find out whether it is you or the lens that is at fault.
I have the 70-300 and have no problems with sharpness at 300mm, handheld and without IS.
as you may know, this lens is not the quickest in the bag to AF, but once locked in, seems to be accurate (unless you have a bad example of course)
I would set up on a tripod and go through the zoom range and see what you get.
Not sure why graduated lenses would stop you manual focusing though, I use varifocals with no problems.
one trick with the 75-300 lens is to get somewhere close using MF and then let camera AF, as it will usually lock on to focus quicker.

This lens is very much a love it/hate it lens. I can and does give superb results for some (me included) but others seem to expect miracles from what is a cheap but very versatile lens (it does macro too don't forget)

Ian 28th May 2012 09:38 AM

Re: 70-300 af
 
Right - spotted a problem immediately in the EXIF data - you shot these at the smallest possible aperture (f/22). This means your images are significantly softened by diffraction (try to avoid going beyond f/22) and by reducing the brightness with such a small aperture your shutter speed is only 1/250th. That's good enough for 70mm, but at 300mm I'd be looking for at least 1/500th hand held with IS on and I'd be happier with 1/1000th or even faster if possible. By going back to ISO 100 or 200 you would be able to get more detail and dynamic range, a very acceptable shutter speed at f/8 and the whole image would be more crisp as diffraction softening would have been avoided. I'm pretty sure the shot is in focus, but the problems I have highlighted will have reduced image quality significantly :)

Ian

cychwr 28th May 2012 09:51 AM

Re: 70-300 af
 
There was a recent update for this lens, not sure if it was to do with A.F or manual, possibly could help.

Ross the fiddler 28th May 2012 10:36 AM

Re: 70-300 af
 
Quote:

Originally Posted by cychwr (Post 168370)
There was a recent update for this lens, not sure if it was to do with A.F or manual, possibly could help.

I know Terry has actually done that update. As he actually has the E620, if diffraction & shutter speed are not going to fix all, then he can always adjust the AF setting for that lens (if needed) in the Menu, but Ian's advice should be applied first.

Edit: The f22 is probably the biggest issue with these two photos, from a slow shutter speed & some by diffraction, but on seeing some of the other photos of Terry's recently, the aperture was f11 & they were still a little soft.

I would suggest Terry, that it is better to lose some DoF to gain a faster shutter speed & maybe f5.6 might still have been OK, & increase to f8 if not.

OlyPaul 28th May 2012 11:03 AM

Re: 70-300 af
 
I tend to agree with Ian about the shutter speed and aperture.

Terry I'd also point out that as your age increases so does the need for faster shutter speeds, health problems can also effect your ability to handhold.

I'm guessing like me you are no spring chicken and I know I now need shutter speeds of at least the same as the angle of view (300mm x2 = 1\600sec) even with IS enabled to be sure of sharp shots every time.

When I think that six years ago I could handhold a image like this at a focal length of 150mm (300mm) at 1/40sec and now I would struggle at 1/300sec.

http://www.pbase.com/paulsilkphotogr...e/85278393.jpg

Stewart G 29th May 2012 02:01 AM

Re: 70-300 af
 
I had a similar problem with this combo, tried everything, including a tripod, but couldn't get reliable AF at distance, only closer up. Manual focus was okay, so I tried adjusting the 620's focus (briefly) but without solving the problem. Then I got an E-1, and found it could focus the 70-300 more precisely. Those two are an amazing combo, and have shown me what a sharp lens the 70-300 really is. So my theory is that the E-1's more powerful battery may have made a difference. Perhaps a pattern exists that all the bodies using BLM batteries can drive this lens' focusing motors more accurately? Anyway, it is a fine solution; I almost gave up on that lens--now I'm reluctant to use anything else.

Barkly 29th May 2012 09:23 AM

Re: 70-300 af
 
Thanks for all this advice. I will go down to the lake and re-shot the pics taking onboard Ian's suggestions.

John W 31st May 2012 12:02 PM

Re: 70-300 af
 
Enjoyed this thread great info as I am struggling with the 70-300mm

FlemmingS 31st May 2012 02:38 PM

Re: 70-300 af
 
The 70-300 mm is a splendid lens considering the very reasonable price. Until I got the 50-200 mm SWD it was my favorite lens, but now I use it very rarely, but I am very reluctant to sell it as it is good value for the money.
My advice:
1. Don't rely on AF only I prefer S-af+MF, Simply focus manually until subject is i focus press shutter button half-way to activate AF and fine adjust while holding shutter button half down.
Avoid multiple AAF points and CF.
2. I found 300 mm a bit soft and normally keep focal length under 275 mm.
3 Always use IS when handheld except when panning.

Only complaint is excessive focus hunting I really wished there was a focal delimiter option say 10 meters to infinity.

But bottom line : Great lens


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