How to test lens before purchase?

[wiskiz]

Hi all... Being super new to this hobby, I got a qn to ask..

When we enter the shop (or meet someone to buy 2nd hand) how do we test for the quality and performance of the lens?

So far.. all i know is focus on a particular spot and test the extreme zooms - question is.. what to look out for before knowing if its a good lense?

Thanks for the ans pros...

 

[dRebelXT]

one thing to remember is that, always test the thing before you walk off, and watch out
when the seller takes out a lens from behind a pile of same lens, which 99% is a falty one,
no matter how honest the seller looks like.

 

[tokrot]

one thing to remember is that, always test the thing before you walk off, and watch out
when the seller takes out a lens from behind a pile of same lens, which 99% is a falty one,
no matter how honest the seller looks like.

Sorry, I dun get it. Why 99% faulty? Care to explain? :embrass:

 

[grantyale]

Sorry, I dun get it. Why 99% faulty? Care to explain? :embrass:

He's saying if there are some pieces known to be less than ideal in stock, the salesperson tends to pick them up before the rest.

 

[dRebelXT]

He's saying if there are some pieces known to be less than ideal in stock, the salesperson tends to pick them up before the rest.

yeah, and other salesperson tends to put it behind the pile since it's not intended for their loyal customer, but if the customer is a noobie, it's ok to cheat him/her lah.
i saw this type of behavior after buying a falty thing without testing it on the spot.

 

[haagen_dazs]

couple of things you can do
1) look through the lens against some bright light/sky
purpose : to look for presence of fogging, haze and major dirt particles in lens

2) look at rear element and front element at an angle
purpose : look for serious wipe marks, scratches of lens coating

3) mount lens, press on dof button and look at shutter blades
purpose : ensure blades are not oily and are responsive and close down properly

4) there are other more anal things you can check for like zoom creep, zoom ring smoothness, no loose play after mounting onto lens etc etc.

as for the sharpness and front back focusing problem, you can't really do a complete test there and then.
you probably have to take the risk, go home, do your tests and see if there are any optical problems with the lens.

 

[Silver]

it's ok to bring yr own cam to test on the spot right?

 

[Ren_Hao]

it's ok to bring yr own cam to test on the spot right?

the best option i can think of.
If you dont mind the trouble. Take a few lens, shoot. Load onto computer, than choose the lens based on the pics u see on the screeen

 

[saperboy]

it's ok to bring yr own cam to test on the spot right?

actually, that's should always be the case... since in the end you'll be using your cam to shoot.

 

[dRebelXT]

actually, that's should always be the case... since in the end you'll be using your cam to shoot.

that's always the case for me, but once I was reluctant to bring thinking it's a small purchase,
then a really lousy lens I was ended up with. It's a must to test lens on the spot since salesman
aint going to be 100% honest.

I always found it difficult to tell the salesman "this lens isn't ideal, I want to test a new piece".
;p

 

[DaGimCi C0d3]

just like to share my experience...

Abt 2 weeks back I was looking to buy the Sigma 17-70, Canon Mount. Seems like there is only 1 piece left in the whole of Singapore as all other shops are out of stock except this particular shop (mentioned frequently in CS).

I am also new at buying lenses but I did bring my cam along for testing... I just mount the lens on and took a few shots.. Feels okie... and agreed to buy after some price bargaining.. ;p

Luckily for me, the saleman was interrupted by a phone call and was talking on it for while. So I took out the lens from the box (which was packed nicely by the saleman) and look look see see. While admiring my new lens, i found a stain on the front glass. Quite a obvious one I must add. When the saleman return, I told him about the stain and he insisted that there is nothing there. He tried cleaning but the stain is still there... then i ask if i can return the item if the stain is affecting the pics, and he replied saying that there is warranty mah.. :dunno: where got ppl wanna buy new but faulty lens?? :sweat:

So in the end... needless to say, i did not buy that piece of lens and left... as i step out of the shop, i can hear the saleman grumbling... :dunno:

So what am trying to say is... must try try try and examine examine examine... Dun trust the saleman too much...

 

[erik]

So I took out the lens from the box (which was packed nicely by the saleman) and look look see see. While admiring my new lens, i found a stain on the front glass. Quite a obvious one I must add. When the saleman return, I told him about the stain and he insisted that there is nothing there. He tried cleaning but the stain is still there... then i ask if i can return the item if the stain is affecting the pics, and he replied saying that there is warranty mah.. :dunno: where got ppl wanna buy new but faulty lens?? :sweat:

So in the end... needless to say, i did not buy that piece of lens and left... as i step out of the shop, i can hear the saleman grumbling... :dunno:

So what am trying to say is... must try try try and examine examine examine... Dun trust the saleman too much...

hey thanks for sharing. mind pm-ing me the shop so that I can be careful. haha :bsmilie:

 

[txv611]

The only way to see thru a glass properly requires the use of a torchlight. Unfortunately I do not have the guts to do so cos it makes me look like I am one super fussy stingy customer. Maybe we should all start using a torchlight and makes it a standard practice for all les purchases.

 

[paradigm]

guess that if the seller got nothing to hide, there should be no offense to him/her. Afterall, we are all paying good money and nobody likes having a lemon ...

personally, I prefer to use a torchlight is I am super not sure. Otherwise, I am perfectly fine taking a cam along to test out the lens, shooting at both the tele and the wide, testing out the focusing etc ... looking a light source thru the lens to see if there are any spots etc ...

If IS lens, then test out the IS function ... and finally ask for a 7-day personal warranty ... the guy may not honour it later, but you know who to avoid next time liao ...

hopes this helps ...

 

[jdredd]

if you want to be super sure u are getting a decent copy..

bring laptop and own camera, test card and a tripod.

test card is those with horizontal lines one - put on the counter and shoot at 45 degrees to test for front/ back focusing.

can also shoot newspaper at a distance.. and compare with a photo from a good lens that you might have in a equivalent focal range... or if u dun have.... can ask to try one of their L lenses

but of course, not every shop will entertain this...

i know MS color dun mind.

 

[Prismatic]

Well, it's good to be careful when buying a new lenses always.
But I've seen extremely fussy people too. There was this guy in the same shop which I was buying something from, he was examining this 50mm F1.8 for almost 2 hours!!! Then there was another guy who was buying a Sigma 70-300 macro, he was just looking thru the rear end of the lense like a telescope, and then he says good perspective! I was like, huh???