50mm ED focusing

[crimbo]

Just recovering from Up Helly Aa and now ploughing through 1000+ images from the E620.
One of the lenses I used was the 50mm f2 ED and we will all agree that it is a very good lens...but in low light I found that it hunted a bit and occasionally would lock at full macro extension.
the main problem was not quite focussing on occasion...is this just the lens design, the camera mechanism or the the limitations of the auto-focussing system?





...and with most the images there aint no second chances...

[photo_owl]

Re: 50mm ED focusing

it has a very fine thread focus motor and a long way to go - so if it misses, or the subject moves, or you sway or move the camera, it will take time.

then there's the camera AF systems and which one you are using - diamond normal sensitivity around CP is the best low light solution (if it's an option on your model) by far.

finally, I don't find it makes a whole lot of difference over the type of shots you show (what I call 'event shooting'), in the light levels evident. I have used pretty much all the possible lenses except the 14-35 and 25 summilux and struggle overall with all of them - even with AF assist from an FL50. But I know it's just me 'cos someone on here told me so...

[Guest]

Re: 50mm ED focusing

These seem to have been shot at F2, this will give quite a narrow dof (and even smaller distance in front of focus point), measured in inches at typical portrait distances.

Are you a 100% sure that none of the image is actually in focus (the ladies nose and gentlemens chest hair/necklace look reasonably sharp at this resolution).

Nick

[crimbo]

Re: 50mm ED focusing

These seem to have been shot at F2, this will give quite a narrow dof (and even smaller distance in front of focus point), measured in inches at typical portrait distances.

Are you a 100% sure that none of the image is actually in focus (the ladies nose and gentlemens chest hair/necklace look reasonably sharp at this resolution).

Nick

Nick, as with the previous comment and yours, I am starting to appreciate that if the front focus is off a little the DoF is very narrow and can easily be lost. I used only the centre focus point, as the E620 does not do 'diamond'...

thanks both

BTW...there are no ladies in the squads at UHA but many laydees

[photo_owl]

Re: 50mm ED focusing

I hadn't realised that you were posting these images as examples of failure/problems.

Whilst I am in no way suggesting that this issue is a 'user failure' but, based soley on these 2 images you really gave your AF system little chance, or rather you gave it things to think about.

The first image has your AF point covering various elements over a range of (probably) 8ft - it's just on the ladies shoulder to the left of the dress strap - and the camera probably grabbed the jewelery after a fair bit of hunting/selecting.

In the second I have illustrated it below. In good light it might find something bang on the lower chin to the right - but in poor light there won't be anything to lock onto there so it's will grab the hair/skin/red strap edge which the lower part of the AF point will almost certainly be covering (as shown).



it may well have taken some time to make this decision because there are a lot of choices within the area designated.

I hope this makes sense.

[crimbo]

Re: 50mm ED focusing

Yes...it does make sense...
Do you think using the full set of focus points would help...I have found that too sometimes go way off...if only the 620 had a little firmware upgrade to allow 'diamond'

[photo_owl]

Re: 50mm ED focusing

Yes...it does make sense...
Do you think using the full set of focus points would help...I have found that too sometimes go way off...if only the 620 had a little firmware upgrade to allow 'diamond'

no and yes Chris - never easy is it!

the danger with all points is that the camera may not go where you want - then again as long as you realise this and monitor the indicated AF point selected, this can work well in such situations. You just need to be aware of what matches your requirements ie if the camera selected the eye of the right hand individual in the pic discussed 'result' 'cos that's the plane you are after.

you can also cycle through the AF selections in this mode - again, this works.

you can't just point and shoot - although the evidence will be there after the event!

the other no is that this doesn't replicate the power of diamond AF set up

[Guest]

Re: 50mm ED focusing

It might be worth practising moving the focal point using the controls of the camera, in both cases the choice of central point was not optimal given the shallow dof.

But, alas, there was another factor working against you, 1/50'th of a second is a slow speed to capture people, they have the inconvenient habit of moving and breathing.

Nick

[photo_owl]

Re: 50mm ED focusing

It might be worth practising moving the focal point using the controls of the camera, in both cases the choice of central point was not optimal given the shallow dof.

But, alas, there was another factor working against you, 1/50'th of a second is a slow speed to capture people, they have the inconvenient habit of moving and breathing.

Nick

the problem with that in low light is that the CP is significantly 'better' at AF relative to the others as I understand it.

absolutely agree re shutter speed, then add the poor quality of the light on top of the lack of it; it's sometimes amazing we get anything!

in practical terms the dof is the real killer to perceived sharpness and focus