Probelms with my sigma f1.4 35mm Art

[413x]

Looking into this some more

looks like i am getting some weird AF issues or im doing my testing wrong

tripod,
remote shutter release
test chart at 45 degrees (or near as i can guess)
f1.4
aperture priority

at infinity i seem to get erratic AF results in that two pictures (including refocus) seem to have very different focal planes

Some are on point,
some are back focused
some are front focus

this would be the sort of problem i am seeing in real life
-some pictures are completely out of focus (most) and some (few) are fine
-and where shutter speed doesnt make a difference

all i can think of is something in the setup cannot handle the lighting?
if this is the case then the lens isnt really appropriate

any advice?

 

[Phal]

Testing with a target at 45 degrees can be a bit counterproductive. It's useful to see where your focus is landing but it's making it more difficult to get a good hit by the AF. If you check Google images for 'Camera Focus Calibration' you'll see some setups which include a target that's flat and a 45 degree angled ruler.

This could explain some of the randomness I guess but it's hard to say. Are you testing in live view?

The Reikan Focal software is very particular about having your target orientated the right way and perpendicular to your cameras view.

 

[413x]

Well I'm a bit shocked

Got my 70d today and am having zero problems thus far.
Even in dark dingy evening the focal points seem to match the focal plane
There is a little bit of error but nothing like the complete miss that I used to get.

I know the 70d has a new focus system but thought it was mainly beneficial to live view?

 

[Phal]

Na, 70d focus system was almost if not as good as the 7d so it's definitely a step up

I was surprised at how quick my 7d2 focus was compared to my 70d. I've struggled to find circumstances where the focus struggles to lock! Even when it's dark and in similar light that my 70d struggled with, the 7d2 has been uber hehe

Gratz on the new purchase that that micro adjust done hehe

 

[413x]

Na, 70d focus system was almost if not as good as the 7d so it's definitely a step up

I was surprised at how quick my 7d2 focus was compared to my 70d. I've struggled to find circumstances where the focus struggles to lock! Even when it's dark and in similar light that my 70d struggled with, the 7d2 has been uber hehe

Gratz on the new purchase that that micro adjust done hehe

I can't believe it. Live view tracking works really well.
I would have got the 7d2 but it's just too much. 70d was 600 and 7d2 was 1100 I think

It obviously wasn't the sigma lens then. I will have to try using it outside before I'm certain.
The increased number of focal points (especially focal zone) is a lovely extra

Bought it on a spur when seeing it at 600 and 60d sales for 400.
And as I said before I do make use of the tilt screen especially for macro

Live view and touch is also very nice function

 

[Phal]

I can't believe it. Live view tracking works really well.
I would have got the 7d2 but it's just too much. 70d was 600 and 7d2 was 1100 I think

It obviously wasn't the sigma lens then. I will have to try using it outside before I'm certain.
The increased number of focal points (especially focal zone) is a lovely extra

Bought it on a spur when seeing it at 600 and 60d sales for 400.
And as I said before I do make use of the tilt screen especially for macro

Live view and touch is also very nice function

Yeah I miss the flipout touchscreen a bit for really low shots 70d is nice and I hope all screens are touchscreens/flipouts soon if they can weatherproof them... I mean why not? If you don't lose anything and gain touch focus and a flipout screen then its win win

 

[413x]

I don't really understand the arguments against touch pivot screens.
It's not like you are submerging camera in water.
I know a lot don't like them

I dunno what would have made me want the 7d2 but the pivot would have helped tbh
I have got shots with it I wouldn't have without it (including my favourite ever pic)

From what you say on the 7d2 AF it sure is tempting. Being my first dslr the I didn't really understand the benefit going from 60D to 70D but it's amazing

Iso too. I'd say my 70D at 6400 looks same as my 60D at 800 ish (never let it go above 800 due to noise)

Oh. Main reason for getting it was micro adjust. I think my 120-300mm could do with it too

Might keep 60D for my up coming wedding and stick 17-55mm on it

 

[Phal]

I'm not sure the high ISO noise is that much better with the 70d but it's a little better at least I think.

I think a lot of people whine about touchscreens because they think they'll lose buttons and be expected to perform functions via the touchscreen and that this is somehow worse. I guess nobody likes being forced to change how they work, especially when they're so familiar with how to use their camera but the 7d2 is actually my first without touchscreen (had 650d and 70d) and I definitely miss it... Just not enough to warrant sticking with a 70d hehe

I'd like to think the 7d2 didn't get a flipout touchscreen because of problems making it though and weatherproof enough rather than people not wanting it :/

Now that you can micro adjust, you should be able to fine tune stuff. That Reikan Focal stuff was good on the 70d, fully automated. Just set a few settings and point it at a well lit target and let it try a bunch of different settings to find the best adjustment.

 

[413x]

Looks like this has front focus issue at most distances. +15 MA seems to do the job

 

[Phal]

Was that just with your own manual testing or did you use Focal? Just curious

My Sigma 18-35mm needed the most adjustment at the tele end of 35mm and that was something like +17 but everything else was + or - 6 at the most (with my 100mm and 200-400)

 

[413x]

Was that just with your own manual testing or did you use Focal? Just curious

My Sigma 18-35mm needed the most adjustment at the tele end of 35mm and that was something like +17 but everything else was + or - 6 at the most (with my 100mm and 200-400)

This is just with manual testing as yet. Finished up at +11
Is the only lens I was having a problem with that I questioned to this extent

My 120-300mm I think will definitely need it too but not so drastically (and it matters less at f2.8 when targets are far away vs f1.4 with a target at 1m or 2

100mm doesn't need anything, I know that already

Wide angle it isn't really necessary as rarely use a wide aperture

 

[Phal]

100mm doesn't need anything, I know that already

I decided to calibrate my 100mm anyway despite never really noticing an issue with focus and it made a minor adjustment for me so I'll see how that goes (Reikan Focal did)

With things being made to certain tolerances, expecting that your lens will gel perfectly with all bodies it probably a bit naïve so I figure I might as well calibrate it since I already paid for the software!

I did it on my 200-400 too but I'm going to use that for pseudo macro work like I did last summer with a 25mm extension tube for Butterflies and Dragonflies At 560mm with less than 2m focus distance the DOF is still pretty shallow!

Colours were crap so I just made it B&W but I think I should have probably cropped differently now that I look at it again lol

Black and White Dragon by Phal44, on Flickr

 

[Amp34]

Reasons for disliking flip out screens:

Bulk - they stick out more and make the camera more bulky. I like a camera to be as small as possible.
Weatherproofing - an extra point of ingress as already mentioned
Failure - it's another point of failure, whether that be just wearing out over time or catching on a bag when being pulled out, or dropping the camera from a small height and landing with the mechanism open.

I have no issue with touch screen though, as long as it doesn't end up Galaxy esque.

 

[413x]

I don't really like really small bodies.
My gfs old 400d was too small
I definitely prefer the trade offs you get with a pivot screen

My macro L 100mm was always bang on the mark with focus charts
As said may well be different with new body

That's pretty things dof
I've already put up my thinnest dof pic. That was a nightmare

 

[dannyjo22]

Phal I have been doing some more digging on that software since I last mentioned it. Which version did you buy? Does it require outside light as I have seen a few people mention? I will be getting it to tinker with on the 50D but to be used on a 5D3 in a few months or new canon.

 

[Phal]

Reasons for disliking flip out screens:

Bulk - they stick out more and make the camera more bulky. I like a camera to be as small as possible.
Weatherproofing - an extra point of ingress as already mentioned
Failure - it's another point of failure, whether that be just wearing out over time or catching on a bag when being pulled out, or dropping the camera from a small height and landing with the mechanism open.

I have no issue with touch screen though, as long as it doesn't end up Galaxy esque.

I never had an issue with bulk/size/sticking out and the only damage one ever sustained was when I dropped it from shoulder height onto a road surface :\ the flipout screen got bent too far back and the casing cracked a little but it still worked fine.

If they could weatherproof it then I would want it on all cameras.

 

[Phal]

Phal I have been doing some more digging on that software since I last mentioned it. Which version did you buy? Does it require outside light as I have seen a few people mention? I will be getting it to tinker with on the 50D but to be used on a 5D3 in a few months or new canon.

Bought the pro version to have all the features available but can't remember what it cost :\


The outside light thing is for ideal conditions. Studio lights indoors would be fine too I'd imagine since it's just to make sure that your AF has no excuses to focus poorly. Even a good amount of daylight through the window is good.

 

[Phal]

That's pretty things dof
I've already put up my thinnest dof pic. That was a nightmare

Yeah that shot was taken without a tube so I can still get closer :E not bad for a long telephoto but I've had thinner dof on my 100mm obviously hehe

 

[dannyjo22]

Bought the pro version to have all the features available but can't remember what it cost :\


The outside light thing is for ideal conditions. Studio lights indoors would be fine too I'd imagine since it's just to make sure that your AF has no excuses to focus poorly. Even a good amount of daylight through the window is good.

Thanks I think I'm going to give the pro version a try I do keep reading rumours of a newer version though.

 

[Phal]

Thanks I think I'm going to give the pro version a try I do keep reading rumours of a newer version though.

Well the last update was just around the xmas period to bring support for the 7d2 but even that isn't completely supported yet! Might be an update to completely support the 7d2 or something else.