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Focus nightmare. HELP. Advice needed


usccharles

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Hi,

 

so recently i got all of my lenses calibrated to my M8. All six lenses. I was so happy when i got them back because before this i had severe backfocus with all my lenses.

 

but now that all my lenses are all 'in focus' and i've used them for a while, i'm starting to get really anal about my focusing. I took a couple days to test all my lenses across all distances and i'm noticing that each lens, as it goes from min focus to infinity, the focus point shifts so that its off focus in certain areas.

 

for instance, my 75 lux is spot on from min to 5 meters, but beyond that it starts developing front focus. my 50 lux is slightly backfocused at min, but is spot on between 2 to 5 meters, and again backfocuses slightly after that.

 

its driving my crazy. each lens has it own characteristic. there is a zone of distance where it is spot-on in focus and then it shifts to either front or backfocus when outside this zone.

 

my question is, is something wrong with the system? or is this pretty much a limitation of the RF camera systems and lenses with unforgiving digital sensors? i wouldn't mind if all lenses shifted focus in the same manor, but all my lenses act alittle differently and i'm having to re-learn each lens' focus characteristic everytime i change lenses and its driving me crazy. but they all have a sweet spot where the focus is dead on.

 

am i being too anal here or do i need more fine tuning of all my lenses?

 

thank you for comments in advanced.

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charles-honestly there have been countless threads regarding this and im not sure what to think. my cameras have never had this problem various m's up to the m8. my first m8 exhibited very slight back focus but i adjusted that out with the hex key. now everything always seems in focus when i want it to be. i feel like I get perfect focus on both m8 bodies with all lenses, including noctilux but there are some here that can prove to you this is impossible. i hope they're wrong and good luck...B

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My personal opinion is that the M rangefinder focussing system is feeling the strain.

 

Since it was first introduced, a number of things have happened which make focussing life more difficult. Higher resolution, faster lenses, more critical focussing on a digital sensor, shallower depth of field with a cropped image plus the ability to review the image instantly and pixel peep. All conspire to make focussing inaccuracies more obvious.

 

Then add in focus shift with changing aperture - which the rangefinder cannot correct for since the lenses are not aperture coupled to the body - and it's a wonder it works as well as it does.

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My personal opinion is that the M rangefinder focussing system is feeling the strain.

 

Since it was first introduced, a number of things have happened which make focussing life more difficult. Higher resolution, faster lenses, more critical focussing on a digital sensor, shallower depth of field with a cropped image plus the ability to review the image instantly and pixel peep. All conspire to make focussing inaccuracies more obvious.

 

Then add in focus shift with changing aperture - which the rangefinder cannot correct for since the lenses are not aperture coupled to the body - and it's a wonder it works as well as it does.

 

hey mark,

 

i'm leaning towards your opinion too and i also believe its a wonder that it works as well as it does. i'm going to shoot alittle more and try to see if i can get into a comfortable flow with my lenses, and if not, i'm going to take them back in for further adjusting. I also think that technitions need to put in extra attention when adjusting these lenses against digital senors. i don't think quality control in that area has fully materialized, quite understandably, since technitions never had to be as rigorous with the lens calibration with film bodies.

 

cheers and thanks

 

charles

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After all the talk about back focus I could not resist to have an look at my camera as well. The cat brought in an opportunity: a mouse. Now that is a terrific subject to check your focus on. From nose to ears the head is less than inch "deep" and with all the hairs you will notice ANY focus problem. By the way: I treated the dead mouse with all due respect. I mean, how many people stop and look ... I did.

 

I shot the attached pictures out of hand (did not use a tripod ... now that's not so smart to start with) with a summilux 50mm wide open. I cropped the pics to the head, using Aperture. As you can see the focus shifts from the left side (hidden right eye) tot the right (visible eye).

 

All in all it's not a scientific experiment, but I'm convinced that before I start thinking of a malfunctioning camera, I need to train my self more to really "focus on focussing". Before this camera I had a Canon 30D and got quite used to autofocus ... but then again I had little choice of picking my exact spot for focus. And yes, I'll use the tripod more often when shooting at F1.4 and/or low light.

 

So, in short, I'm very happy with the M8 and it brings me back to thinking about what I want to achieve with my camera. I'll go out there and take photographs. Lot's of them.

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Charles, I think you are setting your expectations too high. It's going to be tough to adjust all your lenses to focus accurately at all distances and apertures. If this is your Holy Grail, you're likely to be disappoointed. Probably better to get out and take real pictures.

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Charles, I think you are setting your expectations too high. It's going to be tough to adjust all your lenses to focus accurately at all distances and apertures. If this is your Holy Grail, you're likely to be disappoointed. Probably better to get out and take real pictures.

 

yeah i know what you are saying. but even if its impossible to get it perfect, i just wish my 'sweetspot' for all lenses was at the same distance, say at its minimum, or 1 meter, to give me a good starting point. except right now, my lenses have 'sweetspots' in all differnt spots, and that is giving me a headache.

 

i'm so irritatingly nitpicky sometimes ;)

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Just finished testing my lenses for backfocusing.

One of them, a Summicron 50mm, backfocuses 5cm, object at about 1m and f/2. Stopping down to 2.8 - 4 - 5.6 shifts the backfocus even more (another 2 to 4 cm). In longer distances it gets as long as 50 cm -but I can not tell exactly- . In any case this lens is not very useable as is now.

The rest of my lenses look fine, or almost fine... as much as I can tell.

 

"...My personal opinion is that the M rangefinder focussing system is feeling the strain..."

 

You can say that again! :(

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Jordan, I can't speak for Keith, but I didn't when I got mine. I went out and took a few hundred photographs instead.

 

I prefer to look at the photographs I shoot and see if there's a real world problem. So far there isn't.

 

 

Jordan,

 

Steve summed up exactly what I was about to write - Thanks Steve:)

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Jordan, I can't speak for Keith, but I didn't when I got mine. I went out and took a few hundred photographs instead.

 

I prefer to look at the photographs I shoot and see if there's a real world problem. So far there isn't.

 

Same here .... same healthy procedure .. no isues at all for almost a year now!

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Jordan, I can't speak for Keith, but I didn't when I got mine. I went out and took a few hundred photographs instead.

 

I prefer to look at the photographs I shoot and see if there's a real world problem. So far there isn't.

 

I did the same and many photos were not sharp enough. Today's test explained why, so it was very useful to me.

Do we just need to comment on everything?

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The 6/2007, August, issue of LFI has a good article, "Sense and Sensuality," p 42, that talks about the focus shift issue. Leica lenses are set to focus at maximum aperture and some will vary either way as the lens is stopped down. Suggest reading the article for a better understanding.

M

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