What does IQ means?

[KenRC51]

When I heard you guys saying "this lens has better IQ", I know that I means it has better stats. What makes a good IQ? or what do I look for in spec of a lens to see the IQ?

[kjmdrumz3]

IQ stands for Image Quality. I'm not gonna even pretend I know the technical aspects involved but bokeh, sharpness, clarity all play a role.

[nsjuice]

Ken.. good question.. i should have asked when i first started out..


So many abbreviations, us newbs get lost.

The hardest ones Ive tried to figure out were CA and PP.

Just like in high school i just pretended to know what they were talking about to be cool.

Takes a lot to be part of DCRP crew.

[KenRC51]

Ken.. good question.. i should have asked when i first started out..


So many abbreviations, us newbs get lost.

The hardest ones Ive tried to figure out were CA and PP.

Just like in high school i just pretended to know what they were talking about to be cool.

Takes a lot to be part of DCRP crew.

haha, what is CA and PP? I am totally a newbie in the DSLR stuff.

[jcon]

When I heard you guys saying "this lens has better IQ", I know that I means it has better stats. What makes a good IQ? or what do I look for in spec of a lens to see the IQ?

I dont bother with specs or stats, I judge a lens on its real world use and actual pictures. I dont trust "lab tests" and specs.

If youre lookin at new lenses, take a look at real world sample images, or rent it before you buy. There are plenty of online places to rent from.

Nothing worse than reading a lens has good specs and you get it home and it sucks ass.

[tim11]

I dont bother with specs or stats, I judge a lens on its real world use and actual pictures. I dont trust "lab tests" and specs.

If youre lookin at new lenses, take a look at real world sample images, or rent it before you buy. There are plenty of online places to rent from.
.....

I agree with jcon that you don't judge a lens from lab tests. They should be used as a guide to see the lens potential. Owners' opinions can be very biased so beware of that too. Where I am it's hard to rent a lens and very expensive so I have to pay some attention to those 'lab tests' - no other choice.

....
Nothing worse than reading a lens has good specs and you get it home and it sucks ass.

I know how that feels. Recently I spent $975 on a lens but unfortunately got a bad copy; so not easy when buying a lens you might get a lemon. Make sure you don't damage or scratch it because if that happens you can't get exchange or refund.

[XaiLo]

pbase is one of my favorite places to gage image quality.

[tim11]

CA = chromatic aberation, PP = purple fringe.... they are the same things. It's where the highlight meets the dark area and you see purple bands.

[KenRC51]

CA = chromatic aberation, PP = purple fringe.... they are the same things. It's where the highlight meets the dark area and you see purple bands.

What does it do and why is it important? How do you test for this? Sorry or so many questions. I find that people in the forum are really quick in response and friendly

Btw, this tamron 17-50 f/2.8 is my second copy. My first and second copy was bought from Samy Camera. The first copy I think I got a displayed copy (the salesmen told me it was new). I looked new but have a few finger print on the front and back of the lens. Also the lens hood did not fit, it was a lens hood for another lens. I was not happy with this, so I took it back to Samy Camera for a exchange. The customer services was good, they exchanged it with no hassle and questions asked.

Once I got the second copy of the lens I tried it on my D90 and found out that the second lens (the new one) focus a lot quicker and a little bit more quitter. I do some times wonder if I still have a bad copy. How do I test my lens to see if it is a bad copy? Since I am a newbie I do not know what to look for and know something is wrong by look at the pic or the sound of the lens. Can some of you more experienced photographer tell me how? thanks

[K1W1]

CA generally shows up as a purple edge between areas where there is a big difference in contrast. The edge of a branch against the sky is one example where it often shows.

Good lens show no or almost no CA. Bad lens show lots of CA and ordinary lens show CA under certain circumstances that can always be recreated (same f stop and subject for example)

The good news is that most modern post processing software has controls to remove or at least minimise CA. Also newer cameras such as the D300 (not sure about the D90) also automatically handle CA and remove it as they they are processing the image so you no longer see it as often in your shots.