Olympus 25mm 1.8 VS Olympus 45mm 1.8

I have both and from my experience they are very similar in sharpness wide open (razor sharp in center, and excellent sharpness in corners). Maybe the 25mm is a tad bit sharper, but hardly noticeable. Most of the reviews of the lenses say the same thing. The 45mm wide open will create a more shallow depth of field than the 25mm wide open, so if you take similar framed pictures, more of the subject will be in focus with the 25mm. Maybe this is making you think the 25mm is sharper?

 

No, it won't. For a similar framed picture, DOF is a function of sensor size and aperture only.

You can try it with an online depth of field calculator:
http://dofmaster.com/dofjs.html
Enter, lets say, 25mm, f/2 and a distance of 3 meters and enter 45mm, f/2 and a distance of 5.4 meters, and you will get the same DOF.

What you do see is perspective compression, where with the longer lens the background appears to be closer.

 

My mistake. I was thinking along the lines of cropping the 25mm picture to get a similar frame as the 45mm.

 

For the same subject matter, at the same size in the frame, the 45mm will give more subject isolation or a blurrier background, but what is actually in focus (the DOF) will be the same.

http://howmuchblur.com/#compare-2x-25mm-f1.8-and-2x-45mm-f1.8-on-a-0.9m-wide-subject

 

what camera are you shooting on?.... a stabilsed Oly or a unstabilsed Pany?... might just be camera shake/too low shutter speed


K

 

BOTH!

 

Closing the aperture of a lens by 2 stops from f/1.8 gives f/3.5.

 

You are right. I just deleted my post. I put in 2 for the crop lens and 4 for the FF lens and the curves are identical. Good to know my hunch was wrong - makes me want a fast prime for my Oly even more now.

 

this thread is a typical example of what is so broken about forums

the OP posts a question without enough data to actually come up with a reasonable response, no mention of what camera he is shooting, what he is shooting, examples of the issue.. etc

we get a reasonable response from Verbatimium... which if he had stopped after his first sentence would have been fine...then all hell breaks loose.. Edmunds and Earthquake fly off at a tangent with a bunch of irrelevant technobabble... not trying to get any information from the OP in order to actually understand the question.

Then I seek some clarification from the OP then anfyrt posts a random one word response that probably wasn't meant for this thread, and finally Luckypenguin and gobeatty get into a discussion about a deleted post, which once again doesn't actually address the OP's original question.

sheesh

we have a great forum here.. but unless questions are well defined and responses actually appropriate we will become he new DPR  
peace

K

 

Maybe post a pair of photos?

 

The 25mm/1.8 is about 66lpmm in the center with 49lpmm in the edges from the MTF charts wide open at f/1.8. The 45mm/1.8 on the other hand is about 66lpmm in the center with 46lpmm in the edges from the MTF charts wide open at f/1.8. The results in terms of sharpness should be pretty even. Sample variance of the lenses however could tell a different story. Maybe one of your copies is better than the other. Depending on the distance you are photographing and the subjects that you are photographing, you'll also notice depth of field differences which may make part of your subject slightly blurry depending on the depth of your subject. Most times, a wider lens will also look sharper just because more stuff is in focus than out of focus. Both lenses render differently and I haven't really noticed a huge difference in sharpness but I do notice that the 25/1.8 tends to look more in focus just because of how wide it is when taking a portrait. With the 45mm/1.8, I usually stand further back and try to get the subject farther away from the background to get the look I want.

 

on cursory glance both are good enough wide open that i dont scrutinize the detail difference, if any exist. that is, i shoot both at 1.8 with no reservation. only issue -- which is easily and wholly correctable in post -- is the 25 will have stronger vignetting

of course theyre made for very different purposes so no point in comparing anyway

 

I've never detected any difference in sharpness between my 25 & 45 - wide open or otherwise. They are both excellent. If you're seeing differences, then I suspect you must have a problem. Go check another copy of the 45 if you can.

 

Same problem

Hi,
I performed some "tests" with both my 25mm and 45mm at 1.8.
Pictures taken with 25mm are sharper (not way sharper, but sharper enough to easily notice a difference) than pictures taken with 45mm. I thought I had a bad copy, but thought it could be due to a quality difference between these 2 lenses (after all price tag is not the same). What do you think ? Have you changed yours for another copy and did it get any better?