Lack of sharpness at f1.8 on Canon 50mm STM

I'm surprised to hear folks say it is unsharp wide open. It's supposed to be superior to the older nifty fifty's and they were considered pretty sharp from wide open.

I have this lens but unfortunately no wide open shots thus far. I think a little softness or glow is nice with portraiture and flowers etc. I would be surprised if it wasn't sharp enough by F2.

If you want biting sharpness from wide open then that only usually occurs with more recent designs. My Carl Zeiss Planer 50/1.4 ZE has a little glow wide open but that is part of its charm. It not only looks more natural but it gives a creamier look to oof areas..

You've now got me wanting to test the STM lens wide open just to see if my copy is soft!

https://www.flickr.com/photos/normanjshearer/

norman shearer wrote:

I'm surprised to hear folks say it is unsharp wide open. It's supposed to be superior to the older nifty fifty's and they were considered pretty sharp from wide open.

I had (until I left it on a restaurant table) the version before the STM.  I believe that there was a fair amount of copy variation, with some very good and some disappointing, but the photo below was the very first I took from nearby the shop I bought it from so I could easily go back if I wasn't reasonably happy.  And on my 450D too.

Maybe folk with high res screens will find issue with it but I was happy.

What exactly are you trying to shoot at f/1.8? Is there some particular reason? If you are trying to do portraiture, you may be able to catch focus on the eyes but the tip of the nose and a lot of the head will fall out of focus. I'm thinking that you are not clear on the relationship between aperture and depth of field.

If you are looking at focusing at 2m (6 ft) at f 1.8 then the depth of field (eg acceptable sharpness) is 9mm or 3/8 of an inch. Drop to 1 m and DOF drops to 2mm. Could this be a part of the problem?

The impression some folks are giving of this lens wide open - a miss focus of course

if you need to zoom in to be critical of the sharpness then you are a pixel peeper rather than a photographer.

My hat turned backwards so I can shoot portrait style - not how I usually have it!

I had 5D Mk2 mainly because I have not put a strap on it yet - plus the Carl Zeiss lens.

Now I have a 5D Mk2 will I still use the Mk1 - that is the question!

All pics taken wide open by my 10 year old grandson who was using my 5D Mk1 for the very first time.

I will have to try this lens on the Mk2 and see if the focus needs some micro adjustment which is a possibility and I suspect part of the perceived variability. That said I think it is sharp enough on the 5D Mk1 to not be a concern,

if you need to zoom in to be critical of the sharpness then you are a pixel peeper rather than a photographer.

I don't know that I would agree with that statement. What is ok for a family snapshot with a Dutch angle horizon posted on FaceBook may not be suitable if the image is intended for other purposes.

John Sheehy wrote:

norman shearer wrote:

All pics taken wide open by my 10 year old grandson who was using my 5D Mk1 for the very first time.

Looks like you may have done some cropping, which we really need to know to consider how the DOF is working out. Standing farther away and cropping increases DOF, and also brings the background relatively closer to the subject.

just a little off the top..

I will have to try this lens on the Mk2 and see if the focus needs some micro adjustment which is a possibility and I suspect part of the perceived variability. That said I think it is sharp enough on the 5D Mk1 to not be a concern,

You can look at that from two perspectives; if the camera you have is a 12.5MP FF, then there is less visible penalty for using a softer lens than there would be with a 21MP FF, but the 21MP will always have more resolution than the 12.5MP, even if the pixels look sharper from the 12.5MP at 100% pixel view.

I plan to test it on the 5D Mk2 soon although the recent arrival of the 70-200/F4L IS needs testing too. I guess I'll take out both bodies again and have the 50mm on the Mk2 this time.

One plus for the original 5D, however, is that its color filters are stronger and separate color better than the 5D2's filters, when you are shooting well-exposed images at low ISOs.

I didn't know they weakened the Bayer filter on the 5D2. I knew the colors changed on every model and some folks disliked the changes enough to revert back to earlier models. I've yet to form an opinion on that yet though.

Chesapeake Imagery wrote:

if you need to zoom in to be critical of the sharpness then you are a pixel peeper rather than a photographer.

I don't know that I would agree with that statement. What is ok for a family snapshot with a Dutch angle horizon posted on FaceBook may not be suitable if the image is intended for other purposes.

This thread is about sharpness of a lens wide open, not how skilled or otherwise my grandson is. Frankly your rudeness may be acceptable on Twitter but is not appreciated here..

norman shearer wrote:

Chesapeake Imagery wrote:

if you need to zoom in to be critical of the sharpness then you are a pixel peeper rather than a photographer.

I don't know that I would agree with that statement. What is ok for a family snapshot with a Dutch angle horizon posted on FaceBook may not be suitable if the image is intended for other purposes.

This thread is about sharpness of a lens wide open, not how skilled or otherwise my grandson is. Frankly your rudeness may be acceptable on Twitter but is not appreciated here..

Well, I'm sorry that I offended you but my point, in response to your statement stands. If you are doing paid work for a client you should "pixel peep" AND you are a photographer. Family snapshots are another story. Your blanket statement about pixel peeping was rather harsh, I would say.

Chesapeake Imagery wrote:

norman shearer wrote:

Chesapeake Imagery wrote:

if you need to zoom in to be critical of the sharpness then you are a pixel peeper rather than a photographer.

I don't know that I would agree with that statement. What is ok for a family snapshot with a Dutch angle horizon posted on FaceBook may not be suitable if the image is intended for other purposes.

This thread is about sharpness of a lens wide open, not how skilled or otherwise my grandson is. Frankly your rudeness may be acceptable on Twitter but is not appreciated here..

Well, I'm sorry that I offended you but my point, in response to your statement stands. If you are doing paid work for a client you should "pixel peep" AND you are a photographer. Family snapshots are another story. Your blanket statement about pixel peeping was rather harsh, I would say.

Your point it seems was extremely well hidden. No mention of sharpness that I can see.

My blanket statement was just that. Clearly there can be found exceptions to the rule when you make such a statement. My point was aimed at pixel peepers and gearheads who look for minute differences in performance whilst neglecting the art itself. I'm guilty myself, which is why I'm knowledgeable on the subject!

John Sheehy wrote:

Tannin wrote:

Note that some lenses are so beautifully made that you can ignore the normal rules. I habitually shoot a Canon 600/4 wide open at f/4 for example, I expect perfect sharpness at f/4, and get it. But it weighs 4 kilograms and cost $15,000.

This is why generalizations are wrong. I read all the time "lenses are sharpest at f/8" or "lenses are sharpest 2 or 3 stops down from open", and I think of my 400/4DO II, which is sharpest wide open, at f/4.

I would be VERY VERY upset if a $8000 lens was not sharp wide open.  You think that's a good example ?

KenMT wrote:

If you are looking at focusing at 2m (6 ft) at f 1.8 then the depth of field (eg acceptable sharpness) is 9mm or 3/8 of an inch. Drop to 1 m and DOF drops to 2mm. Could this be a part of the problem?

That's a nice way to put it

photo_ion wrote:

50 STM is sharp in the center, for sure there is improvement stopping down, never hesitated using it at 1.8, stopping down only to get proper depth of field, sharpness is overrated (if focus is correct and composition interesting)

Sigma 18-35 is maybe slightly better at 1.8, Sigma 40mm 1.4 should be the king but size / price is an issue...

Great samples. I do recall reviews that said the STM had slightly improved sharpness and contrast in centre but corners need around F2.8 or slower to catch up. Out of focus transition looks nice and smooth and bokeh is much nicer than the old nifty 50's. I think the bokeh improvement alone makes the STM a worthy successor.

On a side note. I have an Olympus 45/1.8 on way for my GX9 and I'll be curious to find out which lens looks the better for portraiture. I opted for the Olympus over a slightly sharper Panasonic lens purely because the Olympus bokeh was smoother and less distracting.