What can u check for when buying a lens?

ManWearPants · 20th January 2009

I would like to know how CSers here go about checking their lens during a purchase? I am assuming that you have already done your homework on which lens you are getting. What I wold like to know is at the point just before purchase, what are the tests you do? I am sure you don't really check for barrel distortion, chromatic abberation, colour fringing, etc. And the shop probably does not allow you to download photo onto a notebook to check for such. Unless you are going to be spending half a day in the shop. What are some of the quick tests that you will do to check that the lens is ok?

jasonteoch · 20th January 2009

i think normally people will just bring their camera, shoot and see if it is sharp...you can then download to your laptop and see the images...i would recommend you to go during the weekday as it is not that crowded...

therat · 20th January 2009

but some of the shop don't allow u to test

I went to CP-P, the saleman say.. cannot test before purchase.
Pay liao then can test.
claim no one want to buy those already tested lens.

Headshotzx · 21st January 2009

Originally Posted by therat

but some of the shop don't allow u to test

I went to CP-P, the saleman say.. cannot test before purchase.
Pay liao then can test.
claim no one want to buy those already tested lens.

Go to the salesman called James. He's the one you should look for if you want to test lenses. I don't like most of the other salesman's attitudes.

What do I do when checking the lens?

Ask for a 5D mark II / 50D for the big and sharp LCD (I don't own a laptop)
Ask to see the lens
Physically inspect to see if there are any dings / scratches to signify it being a used lens
Mount the lens & shoot text on camera boxes or pieces of white paper
Check sharpness / CA (purple fringing)
If the lens has IS, check to see that IS works (viewfinder should stabilise)
Repeat steps 2 to 5 for as many copies of the lens as you want or the store has
Pay and leave being a happy buyer

I went to CP-P to buy a 70-200 2.8IS. I went through 3 copies of the lens on my 400D camera (just because they didn't have the 50D/5D2). One was soft, the second had purple fringing, and the third was soft AND had purple fringing. I went over to John3:16 @ Funan, and I tested both copies that Sam had. Both had no purple fringing, and one was significantly sharper than the other. I bought the best out of the 5 copies I tested.

Cheers,
Zexun

iMac08 · 21st January 2009

Originally Posted by therat

but some of the shop don't allow u to test

I went to CP-P, the saleman say.. cannot test before purchase.
Pay liao then can test.
claim no one want to buy those already tested lens.

is it? i tested 2 copies of 135L before buying. never pay also. i even got him to open up 2 copies of 70-200f4 IS which i din buy at all......

CP allows u to exchange within a week. the guy i buy from told me don't register warranty first. try one week. not happy bring back. but so far my 135L proves to be good.

thenomad · 21st January 2009

Some salesmen have better attitude than the others, and friendlier.
If u happen to meet one, u can go back to the same person if u happen to drop by the same shop.
The rest, don't even bother with them.

engrmariano · 21st January 2009

Originally Posted by therat

but some of the shop don't allow u to test

I went to CP-P, the saleman say.. cannot test before purchase.
Pay liao then can test.
claim no one want to buy those already tested lens.

not true!

i've tested alot of lenses at CP-P & CP-M, only got 70-200 2.8 IS from them and no complain.

therat · 21st January 2009

Originally Posted by iMac08

is it? i tested 2 copies of 135L before buying. never pay also. i even got him to open up 2 copies of 70-200f4 IS which i din buy at all......

CP allows u to exchange within a week. the guy i buy from told me don't register warranty first. try one week. not happy bring back. but so far my 135L proves to be good.

ya..
i went to CP-P last Nov. After someone brought a 17-55 @ a very good price.

I ask for test. The saleman say cannot test and claim the price mention in the forum is not true. He say.. cannot be. cheat u one.

then ask me go and try other shop

therat · 21st January 2009

Originally Posted by engrmariano

not true!

i've tested alot of lenses at CP-P & CP-M, only got 70-200 2.8 IS from them and no complain.

then.. either i bad luck or he see me not up.

he just smile at me and say cannot TEST. NO TESTING

Shin Howard · 21st January 2009

I think the Lens Pricing on CS is for rough guide only.
You gotta email them & ask for a Cash Price E-quote including GST and print it out before you go down to the shop.
(It's only valid for 7 days!)

therat · 21st January 2009

Originally Posted by Shin Howard

I think the Lens Pricing on CS is for rough guide only.
You gotta email them & ask for a Cash Price E-quote including GST and print it out before you go down to the shop.
(It's only valid for 7 days!)

i had email them however until now.. not a single reply from them.
latest one since Nov 08

previous.. i think got 2 yrs liao

Akatsuki · 22nd January 2009

Usually i'll do my homework before purchasing by goggling for pictures taken by the lens and my camera type. For 1st hand lens, if allow testing... best... usually i'll just look @ the physical appearance and take a few random shots @ different setting and a shot at some white background...

TroyP · 22nd January 2009

Originally Posted by Shin Howard

I think the Lens Pricing on CS is for rough guide only.
You gotta email them & ask for a Cash Price E-quote including GST and print it out before you go down to the shop.
(It's only valid for 7 days!)

I call up and get 1 price. My wife call up, they give her different price!
There's nothing wrong with CS priceguide (providing it's fairly recent), it depends who calls up and asks for a quote, and which salesman you speak to.

gunawan · 22nd January 2009

Besides what Zexun mentioned, take note also of DUST in the INNER ELEMENTS.
I've tested a few copies of Sigma's 150-500 and 120-400mm: all was ok in terms of autofocus and sharpness. Almost wanted to buy instalment when i decided to check for dust. phew. got quite a few speckles of dust inside, about 3. How to check?

Open the front lens cap and back lens cover.
Look thru them near a light source.
look at the edge of the light source and all dust inside the inner elements become visible.
U can tell it is inside the lens and not on the front elements by rotating the lens in circular motion, or just get a blower to blow off the front element.

After confirming dust in 2 copies each of the 2 telephotozooms, I ask the salesperson why BRAND new lens got so much dust one? He replied, "Oh, Long Telephoto zoom VERY COMMON have dust one- Mine also have...!!!

I told him, cannot be lah, Brand new leh, so many copies all have dust (but they claim they just brought in from Sigma, especially for me... should I feel touched?)
He replied, aiya, manufacturer must do 'QUALITY CONTROL CHECKING' mah, that's why dust can go in... !!!!??? Quality control checks and dust can go in!!!??? Like that I bring outside to shoot lagi worse right???

And he told me to buy first la, and he will call Sigma to arrange for me to go there and exchange for new one.......

kumhoo · 23rd January 2009

Originally Posted by gunawan

Besides what Zexun mentioned, take note also of DUST in the INNER ELEMENTS.
I've tested a few copies of Sigma's 150-500 and 120-400mm: all was ok in terms of autofocus and sharpness. Almost wanted to buy instalment when i decided to check for dust. phew. got quite a few speckles of dust inside, about 3. How to check?

Open the front lens cap and back lens cover.
Look thru them near a light source.
look at the edge of the light source and all dust inside the inner elements become visible.
U can tell it is inside the lens and not on the front elements by rotating the lens in circular motion, or just get a blower to blow off the front element.

After confirming dust in 2 copies each of the 2 telephotozooms, I ask the salesperson why BRAND new lens got so much dust one? He replied, "Oh, Long Telephoto zoom VERY COMMON have dust one- Mine also have...!!!
I told him, cannot be lah, Brand new leh, so many copies all have dust (but they claim they just brought in from Sigma, especially for me... should I feel touched?)
He replied, aiya, manufacturer must do 'QUALITY CONTROL CHECKING' mah, that's why dust can go in... !!!!??? Quality control checks and dust can go in!!!??? Like that I bring outside to shoot lagi worse right???

And he told me to buy first la, and he will call Sigma to arrange for me to go there and exchange for new one.......

Hey brother, the salesperson seems to be bluffing u... I think he totally know nothing about QC. Haha.

calebk · 23rd January 2009

Originally Posted by gunawan

Besides what Zexun mentioned, take note also of DUST in the INNER ELEMENTS.
I've tested a few copies of Sigma's 150-500 and 120-400mm: all was ok in terms of autofocus and sharpness. Almost wanted to buy instalment when i decided to check for dust. phew. got quite a few speckles of dust inside, about 3. How to check?

Open the front lens cap and back lens cover.
Look thru them near a light source.
look at the edge of the light source and all dust inside the inner elements become visible.
U can tell it is inside the lens and not on the front elements by rotating the lens in circular motion, or just get a blower to blow off the front element.

After confirming dust in 2 copies each of the 2 telephotozooms, I ask the salesperson why BRAND new lens got so much dust one? He replied, "Oh, Long Telephoto zoom VERY COMMON have dust one- Mine also have...!!!
I told him, cannot be lah, Brand new leh, so many copies all have dust (but they claim they just brought in from Sigma, especially for me... should I feel touched?)
He replied, aiya, manufacturer must do 'QUALITY CONTROL CHECKING' mah, that's why dust can go in... !!!!??? Quality control checks and dust can go in!!!??? Like that I bring outside to shoot lagi worse right???

And he told me to buy first la, and he will call Sigma to arrange for me to go there and exchange for new one.......

You want my honest opinion? You're just being anal. Go check even a brand new L lens; it has dust in it. Get real, no lens is dust proof.

If you don't want dust, go to the factory and get them to custom assemble your lens in a clean room, then transport it home in a vacuum casing, leaving it in a clean room. If you ever shoot with the lens, only use it in a clean room. You must, of course, have a lot of cash, and a very interesting, big, clean room to shoot in. There, dust free.

KangS · 23rd January 2009

Originally Posted by calebk

You want my honest opinion? You're just being anal. Go check even a brand new L lens; it has dust in it. Get real, no lens is dust proof.

If you don't want dust, go to the factory and get them to custom assemble your lens in a clean room, then transport it home in a vacuum casing, leaving it in a clean room. If you ever shoot with the lens, only use it in a clean room. You must, of course, have a lot of cash, and a very interesting, big, clean room to shoot in. There, dust free.

Haha... that's very true!

Even the packaging of the lenses present a "dust hazard" !!

Actually, when buying a lens, I think the lens being able to perform up to specification is a whole lot more important that a few small specks of dust. What good is a 'clean' lens that had a mis-focussing drive system ?

From what I've seen, its a whole lot easier to clean up a few specks of dust than it is correct for errors like a de-centered lens element. I've chat at length before with one of service technicians doing lenses, and that's his exact sentiment.

gunawan · 27th January 2009

Originally Posted by KangS

Haha... that's very true!

Even the packaging of the lenses present a "dust hazard" !!

Actually, when buying a lens, I think the lens being able to perform up to specification is a whole lot more important that a few small specks of dust. What good is a 'clean' lens that had a mis-focussing drive system ?

From what I've seen, its a whole lot easier to clean up a few specks of dust than it is correct for errors like a de-centered lens element. I've chat at length before with one of service technicians doing lenses, and that's his exact sentiment.

Another cs bro also complained his L telephotos also got several specks of dust after going through many copies. Plus my own experience, I suppose having dust in brand new telephoto lens are the norm (and having paying so much for it too). I guess there are 2 ways of going about it: One is to live wif it, the other is to purchase it, and send it to the distributor to have the dust cleaned off, and risk having the calibration knocked off in the process...

Shen siung · 28th February 2009

My not so expensive lens also got a dust spec inside, i think as long as it doesn't not affect the quality of the picture (not too big to be visible), it is fine

Octarine · 28th February 2009

The further away the dust is from the sensor the less visible it becomes in the pictures. Even for dust directly on sensor surface one needs f/11 and above. I remember a picture posted here not long ago where one would say "Ok, seems to be a really dirty filter." - and finally there was a huge crack in the front element, centrally. So much about the relevance of dust particles within the lens ...

20th January 2009	#1
ManWearPants Member Join Date: Jul 2008 Location: Singapore Posts: 993	What can u check for when buying a lens? I would like to know how CSers here go about checking their lens during a purchase? I am assuming that you have already done your homework on which lens you are getting. What I wold like to know is at the point just before purchase, what are the tests you do? I am sure you don't really check for barrel distortion, chromatic abberation, colour fringing, etc. And the shop probably does not allow you to download photo onto a notebook to check for such. Unless you are going to be spending half a day in the shop. What are some of the quick tests that you will do to check that the lens is ok?

20th January 2009	#2
jasonteoch Member Join Date: Mar 2007 Posts: 213	Re: What can u check for when buying a lens? i think normally people will just bring their camera, shoot and see if it is sharp...you can then download to your laptop and see the images...i would recommend you to go during the weekday as it is not that crowded...

20th January 2009	#3
therat Member Join Date: Nov 2003 Location: Bedok Posts: 287	Re: What can u check for when buying a lens? but some of the shop don't allow u to test I went to CP-P, the saleman say.. cannot test before purchase. Pay liao then can test. claim no one want to buy those already tested lens.

21st January 2009	#6
thenomad Member Join Date: Nov 2008 Location: Perth Posts: 294	Re: What can u check for when buying a lens? Some salesmen have better attitude than the others, and friendlier. If u happen to meet one, u can go back to the same person if u happen to drop by the same shop. The rest, don't even bother with them.

21st January 2009	#10
Shin Howard Member Join Date: Feb 2008 Location: West Region Posts: 920	Re: What can u check for when buying a lens? I think the Lens Pricing on CS is for rough guide only. You gotta email them & ask for a Cash Price E-quote including GST and print it out before you go down to the shop. (It's only valid for 7 days!) __________________ I'm looking at a different perpective of life.

22nd January 2009	#12
Akatsuki Member Join Date: Mar 2008 Location: Serangoon Posts: 750	Re: What can u check for when buying a lens? Usually i'll do my homework before purchasing by goggling for pictures taken by the lens and my camera type. For 1st hand lens, if allow testing... best... usually i'll just look @ the physical appearance and take a few random shots @ different setting and a shot at some white background... __________________ Alan - Nostalgia Photography Some Primes, Some Zooms, Some Ls

22nd January 2009	#14
gunawan Member Join Date: Nov 2008 Posts: 321	Re: What can u check for when buying a lens? Besides what Zexun mentioned, take note also of DUST in the INNER ELEMENTS. I've tested a few copies of Sigma's 150-500 and 120-400mm: all was ok in terms of autofocus and sharpness. Almost wanted to buy instalment when i decided to check for dust. phew. got quite a few speckles of dust inside, about 3. How to check? Open the front lens cap and back lens cover. Look thru them near a light source. look at the edge of the light source and all dust inside the inner elements become visible. U can tell it is inside the lens and not on the front elements by rotating the lens in circular motion, or just get a blower to blow off the front element. After confirming dust in 2 copies each of the 2 telephotozooms, I ask the salesperson why BRAND new lens got so much dust one? He replied, "Oh, Long Telephoto zoom VERY COMMON have dust one- Mine also have...!!! I told him, cannot be lah, Brand new leh, so many copies all have dust (but they claim they just brought in from Sigma, especially for me... should I feel touched?) He replied, aiya, manufacturer must do 'QUALITY CONTROL CHECKING' mah, that's why dust can go in... !!!!??? Quality control checks and dust can go in!!!??? Like that I bring outside to shoot lagi worse right??? And he told me to buy first la, and he will call Sigma to arrange for me to go there and exchange for new one.......

28th February 2009	#19
Shen siung Member Join Date: May 2008 Posts: 1,436	Re: What can u check for when buying a lens? My not so expensive lens also got a dust spec inside, i think as long as it doesn't not affect the quality of the picture (not too big to be visible), it is fine

28th February 2009	#20
Octarine Member Join Date: Jan 2008 Location: Pasir Ris Posts: 3,583	Re: What can u check for when buying a lens? The further away the dust is from the sensor the less visible it becomes in the pictures. Even for dust directly on sensor surface one needs f/11 and above. I remember a picture posted here not long ago where one would say "Ok, seems to be a really dirty filter." - and finally there was a huge crack in the front element, centrally. So much about the relevance of dust particles within the lens ...