got my sigma 18-35mm 1.8 art lens.

dannylightning · Dec 7, 2015

jaomul said:
Try this (in good to great bright light)

Put a page with small text on a wall or door rigid with tape. Set the camera on a tripod same height as the writing so you are pointing lens directly on the surface, lens is perpendicular to text.

Put lens at 30mm and go 1500 mm between lens and text, focus on live view, take a shot. Now go out of live view and take a series of shots starting at -20,-15,-10, -5,0,5,10,15,20 , but between the shots go into manual focus and defocus shots so the lens has to find focus from oof each time. Make note of what shot equal what adj. Check all photos, on screen or on a computer and see which one closest matches your lives view shot. If you get one that matches your in business at least for 30mm but the fact it's a wide enough angle lens it's probably adjust well enough, use f1.8 for this throughout

just did it exactly how you said, used my speed light to make sure i had enough light. +10 on the fine tune was the closest to the live view photo but not perfect. i am guessing where i had it at +13 was probably really close to where it should have been.

Parker219 · Dec 7, 2015

Wow, this is so weird...

I have the D7200 and 18-35mm 1.8 Art lens and I went to the local camera store TODAY for this same issue...

Basically what we found out is the lens is horrible in live view. It didn't know what to focus on and all the photos were off.

Then the guy changed the camera to a single focus point and looked through the view finder and BAM...issue resolved.

This was the camera trying to focus in live view....horrible....it looks like it is front focusing by A LOT...

Then he took it out of live view and changed it to single focus....perfect!

Then I came home, went in the backyard, and took a picture of a wasp....not bad for not being a true macro lens...it looks like the focus is on the body and not the eyes. I thought I had the focus on the eyes, but either the wasp or me could have moved a fraction of an inch.

dannylightning · Dec 7, 2015

Parker219 said:
Wow, this is so weird...

I have the D7200 and 18-35mm 1.8 Art lens and I went to the local camera store TODAY for this same issue...

Basically what we found out is the lens is horrible in live view. It didn't know what to focus on and all the photos were off.

Then the guy changed the camera to a single focus point and looked through the view finder and BAM...issue resolved.

This was the camera trying to focus in live view....horrible....it looks like it is front focusing by A LOT...

View attachment 112435

Then he took it out of live view and changed it to single focus....perfect!

View attachment 112436

Then I came home, went in the backyard, and took a picture of a wasp....not bad for not being a true macro lens...it looks like the focus is on the body and not the eyes. I thought I had the focus on the eyes, but either the wasp or me could have moved a fraction of an inch.

View attachment 112437

nice photo of the wasp, that looks good and your lens seem to be ok but mine is off. my main concern here is should i send it back since its so far off, i mean i can get a proper tune on the lens but seems to me that it should not require that much of a tune.

I do not use live view ever, i did use it for that last test but i focused manually when in live view so i could set the focus to where it was sharpest since the lens cant seem to get a good focus on its own . all the other shots taken were not in live view and set to a single focus point. so i guess we had a different issue going on here.

here are 2 photos, not in live view and set to a single focus point. first one is without any fine tune, the other has the fine tune at +13 you can see one it is very close to where it should be..

Dillard · Dec 7, 2015

If it concerns you, then send it back. If you're fine with knowing you have to shoot it with a +13 on the fine tune to get the same results you would, then keep it. There is no right or wrong here, just what your comfortable with.

dannylightning · Dec 7, 2015

Dillard said:
If it concerns you, then send it back. If you're fine with knowing you have to shoot it with a +13 on the fine tune to get the same results you would, then keep it. There is no right or wrong here, just what your comfortable with.

i do not know if that is normal for a lens to need that much tune or not, i guess that is why i am concerned, it seems like allot to me which makes me think maybe its a bad copy of the lens but i do now know for sure. if that is pretty normal that i am fine with it but if that is abnormal i would rather have one that is normal.

i get really worked up over stuff like this, i guess i think everything should be perfect out of the box or at least close to it.

killerseaguls · Dec 7, 2015

So, I'm ignorant here. What does tuning the lens mean? Do you have to do this with all lenses??? Or, are we talking about the adjustment on the eye piece if you needed to wear glasses?

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dannylightning · Dec 7, 2015

killerseaguls said:
So, I'm ignorant here. What does tuning the lens mean? Do you have to do this with all lenses??? Or, are we talking about the adjustment on the eye piece if you needed to wear glasses?

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if the lens does not focus perfectly on the the subject you have back or front focus going on. some camera bodys have a auto focus tune available so you can fix the incorrect auto focus issue for each lens. if you have perfect focus you will have sharper images.

generally the lenses i have had require no or very little tune to get perfect focus. this lens how ever requires a good amount of tuning. you can get 5 of the same lens and they could all be a little different or they could be all the same.

i think the D7XXX series and the full frame cameras have a built in AF fine tune. lower models do not..

i got to get to work, did not watch this video since i do not have time but i assume this would explain it. lol

kap55 · Dec 8, 2015

dannylightning - do you have the Sigma USB dock? It would allow you to do fine tuning of your lens without using the in camera adjustment. You have a couple of Sigma lenses that can utilize the dock so I think it's something you may want to consider for the 50-60 bucks it costs. I've used mine on a Sigma 24-205 Art and a 150-600 Contemporary and found it quite worthwhile. It's not going to help if your lens is a dud and needs to be exchanged, but will help when you get a good copy.

dannylightning · Dec 8, 2015

kap55 said:
dannylightning - do you have the Sigma USB dock? It would allow you to do fine tuning of your lens without using the in camera adjustment. You have a couple of Sigma lenses that can utilize the dock so I think it's something you may want to consider for the 50-60 bucks it costs. I've used mine on a Sigma 24-205 Art and a 150-600 Contemporary and found it quite worthwhile. It's not going to help if your lens is a dud and needs to be exchanged, but will help when you get a good copy.

i do have the dock, my sigman 150-600 is dead on accurate all the time so the dock is really not needed for that lens fortunately. i did use it to change the focus speeds and stabilization though which is nice but does not make that much of a difference.

one problem with that as i said earlier, AF fine tune in the camera is reading my 18-200 and my 18-35mm as the same lens. my 18-200 needs a adjustment of -3 to get what seems like just the right focus. i actually deleted the fine tune for the 18-200 and put the sigma back on and it now said it was a fine tun for the 18-35 1.8 so it seemed to work, than i put the nikon back on to fine tune it and the camera still read that lens as the 18-35mm and had the +13 fine tune on it that i had for the sigma..

i guess i could leave the camera at -3 so my nikon lens has the correct adjustment and than adjust the sigma lens accordingly but i cant have a fine tune in the camera for each lens. now i just sold off some lenses to buy this one, all of them had their own fine tune and there was no issue, but when this new lens and the 18-200 there is some sort of issue where the camera reads both lenses as the same after one of them has had a fine tune on it.

i did a google search for sigman 18-35mm fine tune and i am seeing lots of people having focus issues with this lens, before that goodgle search i just did i found nothing but good reviews of this lens. but one website i just was reading said they had a total of something like 8 of these lenses to test and none of them would focus correctly. they did fine tunes on all of them but could not fix the problem. they said it got better after the tune with the dock but the focus was hit and miss and allot of the images they took were not usable., sometimes it would be dead on, some times it missed focus pretty bad.. i read a few other reviews that were saying their copy had major focus problems too. i wish i would have found this infor before i ordered this lens.

one thing i notice even after i did the fine tune and i take several photos of the same subject some look to be in focus better than others so i am not feeling too confident about this lens at the moment.

here is a link to one of those reviews where they were having issues. Sigma 18-35mm Autofocus: A Second Look - Hands-on Reviews | PentaxForums.com

Peeb · Dec 8, 2015

Sigma 18-35 1.8 Focus Problem - only in view finder focus - Other Manufacturers Discussions on Nikon Rumors Forum

dannylightning · Dec 8, 2015

I decided to try the dock. shooting 18mm, 24mm, 28mm, and 35mm each at the 4 different focal lengths that are adjustable. and i chose about 6 different things to shoot at each focal length and each distance. when ever subject was nice and sharp i was happy.

the 1 meter - infinity setting was a pain. had to take several photos of each thing every time to see if they are sharp, focus did not seem consistent at 1 meter or farther away. focus seemed nice and consistent closer than 1 meter and images are now very sharp... adjusting 35mm between 1 meter and infinity was the worst of all for some reason focus was the least consistant.

here is what i ended up with, pretty ridiculous its that much difference

Peeb · Dec 8, 2015

OK- so it 'sees' the 18-35 now? Good. Thought I understood it interpreted both lenses to be the long one earlier.

Does it function correctly now?
Still debating about returning?

dannylightning · Dec 8, 2015

the camera sees both lenses as the same when one of them already has a fine tune. never messed with the dock till today, took me about 4 hours to tune that darn lens. adjust, check photo, pull lens off, put on dock, adjust, check photo, pull lens off, put on dock. over and over and over again.

this weekend if its not raining i plan to go out and really test thing thing out now. as long as i get a good constant focus on my shots ill keep it after spending all that time. i just hope the focus will be consistent or i wont be a happy camper. up close the focus seems great. farther away from stuff we will see..

delete the fine tune and put either lens on the camera and it will recognize that lens. put the other lens on and it still thinks it is the first lens that you have already tuned. very strange.

so i deleated all of the fine tune, put the nikon lens on and set it to -3 where it needs to be. than i put the the sigma on with that fine tune and adjusted it in the dock. so the sigma and the nikon have a -3 each time they are put on the camera. but the sigma also has the dock tuning, unfortunately that is the only thing i can do if i want both lenses to be tuned..

here are a couple photos of my owls after i have finished the fine tune. first one is at f/1.8 the second one at f/2.5

dannylightning · Dec 8, 2015

2 more photos

dannylightning · Dec 9, 2015

some more photos, went walking around tonight to see how it did, seems alright so far at night. i guess i should have turned auto iso off but i was not thinking about it till i got home, so the night shots are a bit noisy.

now i just need to see how it does during the day. so far so good.