Worth buying an auto focus lens?

Loganberry · 12-01-2015, 08:29 PM

I'm new to digital cameras. No idea whether an auto focus lens is a good idea. Do they make life easier? Does the camera have features that work better with an auto focus. Plenty of second hand ones on ebay to try. Are there any recommended ebayers or any to beware of?

VoiceOfReason · 12-01-2015, 08:33 PM

Autofocus makes life much, much more easy.

What camera do you have? What kind of pictures do you plan on taking? That will help answer things.

**pepperberry farm** · 12-01-2015, 08:54 PM - **1 Like**

and plenty of sellers right here in the Marketplace...

mee · 12-01-2015, 09:09 PM

Yes, you should try Autofocus lenses. You are using a K-50 so you have a lot of options available to you!

Any of the Pentax branded lenses with 'WR' in the name mean they have weather seals on them. Using specifically those with your K-50 will give you some degree of 'protection' in wet/humid conditions.

The bonus with an AF lens is you can set the camera to AF or Manual depending on how you like to shoot. So it is almost like 2 lenses in one.

Manual lenses though of course don't have such a feature. It is manual no matter what (even if the camera body is set to AF mode).

The most confusing thing to me starting out was when people said Auto or Manual. Because there is Auto/Manual FOCUS and APERTURE.

There are manual lenses that are also manual aperture (have to press the green button to meter). There are manual lenses that are auto aperture (no need to use green button). There are auto lenses that do both.

For this alone, I'd get a Pentax DA 18-55 WR or DA 18-135 WR and practice shooting with those. It will make life easier with a fully auto lens.

**UncleVanya** · 12-01-2015, 09:37 PM

Auto focus makes some shots a lot easier... But it can fail to nail a shot as well. Hard to know without trying.

**Alex645** · 12-02-2015, 12:29 AM

Learning to autofocus well, in many ways, takes as much practice and good technique as mastering manual focus. In fact, shooting video professionally is almost taboo to use autofocus. However, most pro photographers now use autofocus although elite glass like Zeiss lenses are typically manual focus only.

IF your eyes are still sharp and you've got a nice bright pentaprism finder, like those found on Pentax DSLRs, then I think most autofocus lenses or those that focus by wire, are more difficult to focus manually.

However if you're like me, and your eyes are not like they used to be, I find autofocus (and quick shift) a blessing in most situations. The key is really getting familiar with all the AF options on the camera and knowing there's more technique to doing it well and there is a bit of learning so you won't be frustrated that it isn't always as fast or on your focal point as intended.

One last consideration is noise. There are situations where I've found the AF motor intrusive to the subject or environment of where and when you're shooting.

lytrytyr · 12-02-2015, 08:01 AM

Originally posted by Loganberry

No idea whether an auto focus lens is a good idea. Do they make life easier?

If you use AF mindlessly, it will help you 70% of the time, and let you down for the remaining 30%.

With each AF lens and each camera body, you really need to learn when you cannot rely on AF.

One issue is when the AF spot area covers more than you think it does,
and the camera decides to choose the background rather than the subject.

Again, many standard zoom lenses have a hard time with viewfinder AF at the wide end,
or you may have a lens like my DA 70 which handles AF well at a distance, but not close up.

Your options are to fiddle with the AF adjustment in the camera settings,
or slow down and use the AF from LIve View, which is usuallly more accurate.

Personally, I find using MF more relaxing - I don't have to worry about second-guessing the AF system.

**Just1MoreDave** · 12-02-2015, 09:43 AM

You probably have to buy an autofocus lens to get wide angle coverage at a reasonable price. Manual focus lenses wider than 28mm were less common, hard to make and more expensive on film. The supply is low and prices high today. Samyang makes some excellent modern versions but also not cheap. An ordinary DA 18-55 is what, 50-60 bucks? I have a couple of 24mm manual focus lenses that are sharper and faster, but worse at flare or contrast. And 24mm is not that wide.

AF lenses have more communication with the camera so they do allow the camera to do more. The camera knows the focal length so you don't have to manually set that for SR to work. Some flashes use that focal length information to control a zooming flash head. Lenses with variable aperture can tell the camera where their maximum aperture changes for more accurate exposures. The camera can confirm focus at points all around the frame, not just the center point. The lens name is attached to the metadata of the image, sometimes useful later - some third party lenses don't support this properly.

nomadkng · 12-02-2015, 10:15 AM

Originally posted by Loganberry

I'm new to digital cameras. No idea whether an auto focus lens is a good idea. Do they make life easier? Does the camera have features that work better with an auto focus. Plenty of second hand ones on ebay to try. Are there any recommended ebayers or any to beware of?

Originally posted by VoiceOfReason

Autofocus makes life much, much more easy.

What camera do you have? What kind of pictures do you plan on taking? That will help answer things.

Voice of Reason asked all the relevant questions, because you original post is too opened ended.

You must also take into account, budget and shooting style. Zoom or prime? Wide angle or telephoto? Low light? Good light? How is your eyesight?

But to try and give you a quick answer - for landscape images or most images where you have time to set up a tripod and compose, AF isn't really necessary unless you have trouble discerning critical focus with your own eyes. So you can get a MF high quality (IQ) lens for slightly cheaper than an AF one.

If you or your subject is moving, AF will make a big difference, although there are many skilled photogs who can still nail focus with 400mm A* lenses on a BIF, but that takes years of practice.

I bought a DSLR specifically for AF after shooting a K1000 for 25+ years. It gives me options that I wouldn't have otherwise - the ability to remove one operator step in the image taking process if I needed/wanted. Plus, there have been numerous times I have been using a tripod in awkward or precarious spots where I really couldn't look through the viewfinder and I could barely see the LCD in LV for composition. I had to rely of the AF in those times as well. Could never have pulled off the shot with MF.

Why are you even asking this question? What internal motivation has prompted this thought process?

12-01-2015, 08:29 PM	#1
Loganberry New Member Join Date: Dec 2015 Location: Somerset Posts: 4	Worth buying an auto focus lens? I'm new to digital cameras. No idea whether an auto focus lens is a good idea. Do they make life easier? Does the camera have features that work better with an auto focus. Plenty of second hand ones on ebay to try. Are there any recommended ebayers or any to beware of?

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12-01-2015, 08:33 PM	#2
VoiceOfReason Site Supporter Join Date: Jun 2010 Location: Mishawaka IN area Photos: Albums Posts: 6,124	Autofocus makes life much, much more easy. What camera do you have? What kind of pictures do you plan on taking? That will help answer things.

12-01-2015, 08:54 PM - 1 Like	#3
pepperberry farm amateur dirt farmer Join Date: Dec 2014 Location: probably out in a field somewhere... Photos: Gallery \| Albums Posts: 41,766	and plenty of sellers right here in the Marketplace...

12-01-2015, 09:09 PM	#4
mee Veteran Member Join Date: May 2010 Posts: 7,403	Yes, you should try Autofocus lenses. You are using a K-50 so you have a lot of options available to you! Any of the Pentax branded lenses with 'WR' in the name mean they have weather seals on them. Using specifically those with your K-50 will give you some degree of 'protection' in wet/humid conditions. The bonus with an AF lens is you can set the camera to AF or Manual depending on how you like to shoot. So it is almost like 2 lenses in one. Manual lenses though of course don't have such a feature. It is manual no matter what (even if the camera body is set to AF mode). The most confusing thing to me starting out was when people said Auto or Manual. Because there is Auto/Manual FOCUS and APERTURE. There are manual lenses that are also manual aperture (have to press the green button to meter). There are manual lenses that are auto aperture (no need to use green button). There are auto lenses that do both. For this alone, I'd get a Pentax DA 18-55 WR or DA 18-135 WR and practice shooting with those. It will make life easier with a fully auto lens.

12-01-2015, 09:37 PM	#5
UncleVanya Loyal Site Supporter Join Date: Jul 2014 Photos: Gallery \| Albums Posts: 28,452	Auto focus makes some shots a lot easier... But it can fail to nail a shot as well. Hard to know without trying.

12-02-2015, 12:29 AM	#6
Alex645 Site Supporter Join Date: May 2015 Location: Kaneohe, HI Photos: Albums Posts: 3,527	Learning to autofocus well, in many ways, takes as much practice and good technique as mastering manual focus. In fact, shooting video professionally is almost taboo to use autofocus. However, most pro photographers now use autofocus although elite glass like Zeiss lenses are typically manual focus only. IF your eyes are still sharp and you've got a nice bright pentaprism finder, like those found on Pentax DSLRs, then I think most autofocus lenses or those that focus by wire, are more difficult to focus manually. However if you're like me, and your eyes are not like they used to be, I find autofocus (and quick shift) a blessing in most situations. The key is really getting familiar with all the AF options on the camera and knowing there's more technique to doing it well and there is a bit of learning so you won't be frustrated that it isn't always as fast or on your focal point as intended. One last consideration is noise. There are situations where I've found the AF motor intrusive to the subject or environment of where and when you're shooting.

12-02-2015, 08:01 AM	#7
lytrytyr Pentaxian Join Date: Nov 2011 Photos: Gallery \| Albums Posts: 4,310	Originally posted by Loganberry No idea whether an auto focus lens is a good idea. Do they make life easier? If you use AF mindlessly, it will help you 70% of the time, and let you down for the remaining 30%. With each AF lens and each camera body, you really need to learn when you cannot rely on AF. One issue is when the AF spot area covers more than you think it does, and the camera decides to choose the background rather than the subject. Again, many standard zoom lenses have a hard time with viewfinder AF at the wide end, or you may have a lens like my DA 70 which handles AF well at a distance, but not close up. Your options are to fiddle with the AF adjustment in the camera settings, or slow down and use the AF from LIve View, which is usuallly more accurate. Personally, I find using MF more relaxing - I don't have to worry about second-guessing the AF system.

12-02-2015, 09:43 AM	#8
Just1MoreDave Site Supporter Join Date: Feb 2007 Location: Aurora, CO Photos: Gallery \| Albums Posts: 6,340	You probably have to buy an autofocus lens to get wide angle coverage at a reasonable price. Manual focus lenses wider than 28mm were less common, hard to make and more expensive on film. The supply is low and prices high today. Samyang makes some excellent modern versions but also not cheap. An ordinary DA 18-55 is what, 50-60 bucks? I have a couple of 24mm manual focus lenses that are sharper and faster, but worse at flare or contrast. And 24mm is not that wide. AF lenses have more communication with the camera so they do allow the camera to do more. The camera knows the focal length so you don't have to manually set that for SR to work. Some flashes use that focal length information to control a zooming flash head. Lenses with variable aperture can tell the camera where their maximum aperture changes for more accurate exposures. The camera can confirm focus at points all around the frame, not just the center point. The lens name is attached to the metadata of the image, sometimes useful later - some third party lenses don't support this properly.

12-02-2015, 10:15 AM	#9
nomadkng Veteran Member Join Date: Sep 2008 Location: Phoenix, AZ Posts: 1,448	Originally posted by Loganberry I'm new to digital cameras. No idea whether an auto focus lens is a good idea. Do they make life easier? Does the camera have features that work better with an auto focus. Plenty of second hand ones on ebay to try. Are there any recommended ebayers or any to beware of? Originally posted by VoiceOfReason Autofocus makes life much, much more easy. What camera do you have? What kind of pictures do you plan on taking? That will help answer things. Voice of Reason asked all the relevant questions, because you original post is too opened ended. You must also take into account, budget and shooting style. Zoom or prime? Wide angle or telephoto? Low light? Good light? How is your eyesight? But to try and give you a quick answer - for landscape images or most images where you have time to set up a tripod and compose, AF isn't really necessary unless you have trouble discerning critical focus with your own eyes. So you can get a MF high quality (IQ) lens for slightly cheaper than an AF one. If you or your subject is moving, AF will make a big difference, although there are many skilled photogs who can still nail focus with 400mm A* lenses on a BIF, but that takes years of practice. I bought a DSLR specifically for AF after shooting a K1000 for 25+ years. It gives me options that I wouldn't have otherwise - the ability to remove one operator step in the image taking process if I needed/wanted. Plus, there have been numerous times I have been using a tripod in awkward or precarious spots where I really couldn't look through the viewfinder and I could barely see the LCD in LV for composition. I had to rely of the AF in those times as well. Could never have pulled off the shot with MF. Why are you even asking this question? What internal motivation has prompted this thought process?