Am I asking too much?

I hate to change lens but I may have to start. I use zoom lens almost exclusively but the only lens I have that doesn't require a wide range of AF fine adjustment is the Sigma 100-300/f4. Of course that means the focus on any shot is a crap shot.

What is your experience with AF fine adjustment on your zoom lens. Which one of your lens has a reasonable range of AF fine adjustment and what is that range?

You suggest you have many lenses that all need AF fine adjustment if i read this right. the obvious question is why haven't you got those lenses or the camera fixed? Why do people keep clearly defective equipment when they can just get it fixed? there are so many people since the possibility of AF adjustments that seem to have to have an adjustment on every lens, is it really that bad or are they all fooling themselves. i have a very large quantity of lenses, 13 AF lenses not for sale and none of them need any focus adjustment, i take pictures and if the pictures are in focus then its fine, if not its usually a limitation of the camera or the my fault. however there have been occasions where lenses have failed and i get them serviced, nothing in recent times though.

MightyMike said:

MightyMike wrote:

You suggest you have many lenses that all need AF fine adjustment if i read this right. the obvious question is why haven't you got those lenses or the camera fixed? Why do people keep clearly defective equipment when they can just get it fixed? there are so many people since the possibility of AF adjustments that seem to have to have an adjustment on every lens, is it really that bad or are they all fooling themselves. i have a very large quantity of lenses, 13 AF lenses not for sale and none of them need any focus adjustment, i take pictures and if the pictures are in focus then its fine, if not its usually a limitation of the camera or the my fault. however there have been occasions where lenses have failed and i get them serviced, nothing in recent times though.

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One of us may be an exception. This post may answer that question. I have 6 lens that I actually use. Of those 2 require no adjustment and one of those is a prime. The other 4 are zooms and require an adjustment and that adjustment is different from wide open to fully closed which makes it necessary to pick a mid point and hope for the best.

You may be right. I may be too lenient when I accept a lens or I may just be the norm. I hope to find the answer to that with this post.

I must say that 13 lens with no required adjustment sounds exceptional. Did you return a number of lens until you got one that required no adjustment?

The fact that manufacturers include the AF fine adjustment function would suggest that it may be "normal" for a lens to require some adjustment.

rondeann said:

rondeann wrote:

rondeann said:

MightyMike wrote:

You suggest you have many lenses that all need AF fine adjustment if i read this right. the obvious question is why haven't you got those lenses or the camera fixed? Why do people keep clearly defective equipment when they can just get it fixed? there are so many people since the possibility of AF adjustments that seem to have to have an adjustment on every lens, is it really that bad or are they all fooling themselves. i have a very large quantity of lenses, 13 AF lenses not for sale and none of them need any focus adjustment, i take pictures and if the pictures are in focus then its fine, if not its usually a limitation of the camera or the my fault. however there have been occasions where lenses have failed and i get them serviced, nothing in recent times though.

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One of us may be an exception. This post may answer that question. I have 6 lens that I actually use. Of those 2 require no adjustment and one of those is a prime. The other 4 are zooms and require an adjustment and that adjustment is different from wide open to fully closed which makes it necessary to pick a mid point and hope for the best.

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I can assure you i'm not the exception, i know many people across many brands who have many lenses that don't need AF adjustment, granted there are a few that do. if the problem is with the aperture adjustment its an issue that is less common than which focal length the zoom lens is at. some lenses do have a focus shift as you stop them down, its cause by a change in the not well corrected spherical aberrations, however this is rarely common in a modern lens.

rondeann said:

You may be right. I may be too lenient when I accept a lens or I may just be the norm. I hope to find the answer to that with this post.

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You are too lenient!

rondeann said:

I must say that 13 lens with no required adjustment sounds exceptional. Did you return a number of lens until you got one that required no adjustment?

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I've had lenses that have failed in the past, a Sigma 10-20mm F4-5.6 that stopped focusing to infinity, ditto on a Pentax 10-17, both of which had been serviced and later on replace with different lenses. My first Sigma 100-300mm F4 had issues, these were serviced and then Sigma was nice enough to replace the lens entirely, the new one had a slight FF issue only noticeable at very close range shooting at F4.0 and 300mm, after i had them service the lens because i felt is focus had slowed that issue seems to go away (they took apart the lens and put it back together again). The only other lens i've ever had an issue with is the Tamron 17-50mm F2.8, the first copy was bad, replaced with another copy that also was bad, had bad intermittent focus issues, it took 10 months for the service to figure out the problem and fix it, part of that was my fault for not using the lens much and therefore not encountering the problem and then 10 months were it was perfect before i sold it for another lens. The only lenses i own that need focus adjustment are manual focus lenses when used in conjunction with focus trap, its a common issue that many manual focus lenses require a -10 or so adjustment to get focus spot on with focus trap, i see it more in telephoto lenses and fast lenses, however there are some lenses that just don't need this adjustment either.

rondeann said:

The fact that manufacturers include the AF fine adjustment function would suggest that it may be "normal" for a lens to require some adjustment.

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No! they included it so they wouldn't have to deal with as many service issues related to focus adjustment and because they realized they could implement such a feature. Not because its normal but because it cost less to implement than to fix small issues with some lenses.

I'd far rather have a perfectly working lens then one with a flaw that will cost lots of money if not fixed in the warranty period

Are you suggesting that if I have a lens that requires lets say a +4 AF fine adjustment to produce a good focus range, that lens is defective and should be returned to the manufacturer until it requires no (zero) AF fine adjustment what so ever.

I have to say that for my purposes if I have the choice of making a +4 AF adjustment to get a good focus range or sending that lens back to the manufacturer until it requires zero AF fine adjustment (and the same focus range as the +4 AF adjustment I could have made myself), I will make the adjustment myself. If nothing else it saves the postage and acheves the same result.

My problem occures with a zoom lens when it requires a different AF fine adjustment at the two extreme focus lengths or, for that matter if it requires a different AF fine adjustment for any two focual lengths.

Arguably, I have no need for fine adjustment. Neither does my cam, which wouldn't take one anyway (no support unless, supposedly, in debug mode, global correction only).
Which cam do you use?

The K-20 & K-5 both have Auto Focus Fine Adjustment function. I am talking ablut the K-5.

Sorry I can't help as I only have a k100d (I mainly use zooms).

I believe that the K100d has AF fine adjustment but it's in Debug mode and it would take some investegation to find out how to use it and if you are getting sharp pictures you probably don't need it.

... this whole question of focus accuracy and fine adjustment.

It is something I have struggled with for years. I was unhappy with the K10D and tried the debug fix but eventually shelled out for the K20D, just to get the lens fine adjustment capability. That camera was, and still is, a fine tool to shoot with. My favourite body to be honest. I actually prefer its' feel to my K-5 and still use it with my longer zooms. Before getting the K-5 I shot 90% of my photographs with the Sigma 17-70 and was quite happy with the results.

I have had the K-5 for over a year now. I used the Sigma lens to begin with but replaced that with the same model Sigma after an unfortunate accident. The replacement lens isn't as good (sample variation?) and I'm now using the Pentax DA18-135 with the K-5 and getting quite good results.

A few observations. I usually "fiddle" with a new lens/camera combo fine adjustment for some time before I'm happy with the output. I only use zoom lenses and tend to adjust them to focus sharply at around 20 to 25 feet and at the most used focal length - generally F5.6 to F8. Most shots focused on a point much further than that are getting into landscape distances (in my case) and depth of field probably takes care of minor inaccuracies. I have a strong feeling (not very scientific, I know) that cameras seem to improve over time with a particular lens. (Without further adjustment). I've noticed this now with several lenses on both cameras. I also believe that the focusing ability or accuracy of a camera definately changes over time. It is further complicated, I believe, by varying light levels and intensities affecting focus. Perhaps the temperature of the gear also affects the focus ability. Here in Australia it can get down to just below zero in the mornings in Winter or the inside of a car can get up to 40 to 50C. There has to be some expansion/contraction in that range of temperature, surely?

And finally, I have noticed that some people here on the forum are less demanding when it comes to sharpness than others.

I have never needed to AF adjust any of my pentax lenses on my K5 - maybe I'm not fussy enough?

rondeann said:

rondeann wrote:

Are you suggesting that if I have a lens that requires lets say a +4 AF fine adjustment to produce a good focus range, that lens is defective and should be returned to the manufacturer until it requires no (zero) AF fine adjustment what so ever.

I have to say that for my purposes if I have the choice of making a +4 AF adjustment to get a good focus range or sending that lens back to the manufacturer until it requires zero AF fine adjustment (and the same focus range as the +4 AF adjustment I could have made myself), I will make the adjustment myself. If nothing else it saves the postage and acheves the same result.

My problem occures with a zoom lens when it requires a different AF fine adjustment at the two extreme focus lengths or, for that matter if it requires a different AF fine adjustment for any two focual lengths.

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--

Hi,

75% of my lenses need correction, personally, I'm more than bored with returning lenses, three of my zooms returned (Sigma Tamron they're all waiting for parts,phone calls etc) and still all need correction, the DA 21 was messed up by Pentax,I returned it and they sent me another it was great other than it needs -10 on the K5 so I dial in -10 and it's fine, I'm happy. Some are + some -.

It makes me suffer less with " the early greying and hair-loss syndrome" For a full head of hair use AF adjust!


Dave's clichés

Right, your problem is then the common issue when such an issue occurs at 2 ends of the zoom range it requires different AF adjustment making it next to useless, this is when you get it fixed, if the whole thing had just one AF adjustment required then sure do it yourself it is live with-able. but again if AF adjustment issues stop you from enjoying your equipment that you paid big bucks for then get it serviced and don't complain! so all those lenses that don't work with just one correction are wasted money if you don't get them fixed!

Thanks for your comments. Yes I think you're right, many things are at play with AF. I think MightyMike has a good point, within reason. In the future I won't accept a lens if the AF fine adjustment isn't the same throughout the zoom range. This may force me to go to primes and I hate to change lens but I'll do what it takes. If I can't get sharp shots then I may as go to a Point-an-Shoot.

ozdean said:

ozdean wrote:

I have never needed to AF adjust any of my pentax lenses on my K5 - maybe I'm not fussy enough?

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If you're shots are satisfying you then that's all you can ask. Have you tried to calibrate the AF fine adjustment and found it acceptable?

Mike you make a good point and, as I said further down in this thread, in the future I won't accept a lens if I can't get it to calibrate to a single AF fine adjustment value.

Just a suggestion, when you want someone's attention try throwing a marshmallow. When I'm busy dodging rocks I miss a lot of what you say.

=

fair enough, just tired of people not fixing what should be fixed from the moment they receive it.

rondeann said:

rondeann wrote:

I hate to change lens but I may have to start. I use zoom lens almost exclusively but the only lens I have that doesn't require a wide range of AF fine adjustment is the Sigma 100-300/f4. Of course that means the focus on any shot is a crap shot.

What is your experience with AF fine adjustment on your zoom lens. Which one of your lens has a reasonable range of AF fine adjustment and what is that range?

Click to expand...

My sympathies, and I can only go from my own experiences with the K5.

Every lens I have, produced perfect focus, until the day I bought a 31 Ltd. Despite adding + 10 fine adjustment, it was still way OOF. I contacted the seller, as the lens had a 2 year warranty here in France, and they said contact Pentax France. They in turn, said that I had to return all my lenses and the K5 to them and they would have to re-calibrate all the lenses ... To me that seemed quite crazy, as it was only the 31 that I was having problems with. So I tried the same lens on a friend's K5, and it was fine - about 2 steps of adjustment needed.

In the end, I really didn't want to have all the bother, and so sold the 31Ltd, and later the K5. In its place I bought a K-01 and K30, and both these bodies perform absolutely perfectly!

Since then I no longer have any focus problems. Is this a K5 thing that varies from body to body, or is a batch problem? If so, I would be strongly tempted to sell your K5 and get a K30, while waiting perhaps for the K5II or K5IIs. Life is too short .... and the K30 is the bargain of a lifetime ...

I don't think it was the K-5. They wanted all your lens and the K-5 so they could use the debug mode to adjust the AF fine adjustment range within the K-5 to a point that all the lens would fall into it's limits. I believe the way it works is if, for example, all of your lens fell into the range of +5 to -15 they can adjust the center point so that all your lens would be now read from +10 to -10. If that's not the way it works maybe someone will read this post and correct me.