20mm f1.7 vs 40mm 2.8 vs. 75mm f1.8 DOF/Bokeh/Perspective Comparisons

Panasonic 20mm f1.7 pancake @ f1.7:

Olympus 12-40mm f2.8 @ 40mm f2.8:

Olympus 75mm f1.8 @ f1.8

I thought these might be of interest to people trying to see the different levels of background blur for different focal lengths.  I did this by myself, so the framing was a bit rough, and the sun went down for the 20mm shots, but I found them useful.

Here are some less scientific examples, but also useful for DOF and blur analysis (all shots wide open) for the Olympus 75mm f1.8 and the Panasonic Leica 25mm f1.4:

75mm f1.8:

No. The 75 f1.8 cannot blur out distracting backgrounds.

25mm f1.4:

I thought someone might find these helpful for the always confusing lens selection process.

Tony8232 wrote:

There are depth of field charts that give an accurate measure of the various lenses.

Thanks for adding the link.  That definitely adds to the topic, but there's also a big difference between a chart and a photo, and combining that with the compression effects of various lenses makes it even harder to visualize.

I jut wish I had the Panasonic/Leica 42.5 and the Oly 45 1.8 for the comparison shot. I need to do one for the 25.  If anyone has similar full body/ lens wide open kind of shots with either of those lenses, I;d be grateful if you'd post them on this thread.

Tony8232 wrote:

Here is a comparison.
http://www.cameralabs.com/reviews/Panasonic_Leica_DG_Nocticron_42-5mm_f1-2_H-NS043E/bokeh_comparison.shtml

Thanks again.  I'd seen these too, and that's part of my frustration.  Whenever people show off the blurring capabilities of their lenses, they tend to take pictures of small, inanimate objects from close up.  This guy took pictures of beer apparatus.  I want pictures of people from common working distances.  That's why I made my test shots.  They show what each lens is capable of from a set framing point.

I think that people buy lenses based on pictures of beer apparatus, and then are frustrated when they think their lens is going to deliver that creamy, out-of-focus background when they are taking group portraits, particularly with the wider angle, fast aperture lenses.

I am in your exact shoes, thanks for the pics.

One thing helpful to people researching, took me a minute to get this as well, you and I are interested in "shallow DoF" more so than Bokeh, the former being how easy it is to get backround blur, and the latter being how the blur looks *if*/when you can get it. I do want it to look good if I get it (e.g. good bokeh), but the main struggle is just to get human subject + background blur at all.

So if you search '[lensName] bokeh' its correct to expect to see the macro object shots, since they show the bokeh the best. I think the reason serious reviews don't do many shallow dof examples is they expect enthusiasts to know this behavior simply from the aperture, wheres bokeh varies from lens to lens.

Another thing that took me a while to get, is that long lenses are only "sort of" better for shallow DoF for the same subject composition. There is less background due to perspective, so decreases the chance of having unwanted background, and the background is zoomed in so the blur is more apparent, but *same* level of actual detail loss. Also subjectively better for portraits due to distortion, but I personally have several portrait keepers shot at effective 24. I definitely wont be forgoing the usefulness of a more verstile faster prime (the 25mm 1.4) for the supposed portrait benefits of ~80mm. May have both one day but its really far down the list

While I have only tried 2.8 so far (the pany 12-35mm), I've found that if I just do a head, maybe a collarbone, and background is 20yrds + I can get moderate bokeh wide open. Plan to get the 25mm 1.4 soon and, as you have shown in the last photo, expect reasonable blur capabilities for head + upper body shots but probably not full body.

AngelicBeaver wrote:

Tony8232 wrote:

Here is a comparison.
http://www.cameralabs.com/reviews/Panasonic_Leica_DG_Nocticron_42-5mm_f1-2_H-NS043E/bokeh_comparison.shtml

Thanks again. I'd seen these too, and that's part of my frustration. Whenever people show off the blurring capabilities of their lenses, they tend to take pictures of small, inanimate objects from close up. This guy took pictures of beer apparatus. I want pictures of people from common working distances. That's why I made my test shots. They show what each lens is capable of from a set framing point.

I think that people buy lenses based on pictures of beer apparatus, and then are frustrated when they think their lens is going to deliver that creamy, out-of-focus background when they are taking group portraits, particularly with the wider angle, fast aperture lenses.

Will this place help.

http://dofsimulator.net/en/

Tony8232 wrote:

There are depth of field charts that give an accurate measure of the various lenses.

I think those charts have their uses for online debates and theoritical differences but they often don't really give a real idea of what an image will look like in the end. The various sensor crops make things muddier.

AngelicBeaver wrote:

Panasonic 20mm f1.7 pancake @ f1.7:

25mm f1.4 @ f1.4 (taken today):

Olympus 12-40mm f2.8 @ 40mm f2.8:

Olympus 75mm f1.8 @ f1.8

I thought these might be of interest to people trying to see the different levels of background blur for different focal lengths. I did this by myself, so the framing was a bit rough, and the sun went down for the 20mm shots, but I found them useful.

Here are some less scientific examples, but also useful for DOF and blur analysis (all shots wide open) for the Olympus 75mm f1.8 and the Panasonic Leica 25mm f1.4:

75mm f1.8:

No. The 75 f1.8 cannot blur out distracting backgrounds.

25mm f1.4:

I thought someone might find these helpful for the always confusing lens selection process.

averagejoe576 wrote:

I am in your exact shoes, thanks for the pics.

One thing helpful to people researching, took me a minute to get this as well, you and I are interested in "shallow DoF" more so than Bokeh, the former being how easy it is to get backround blur, and the latter being how the blur looks *if*/when you can get it. I do want it to look good if I get it (e.g. good bokeh), but the main struggle is just to get human subject + background blur at all.

So if you search '[lensName] bokeh' its correct to expect to see the macro object shots, since they show the bokeh the best. I think the reason serious reviews don't do many shallow dof examples is they expect enthusiasts to know this behavior simply from the aperture, wheres bokeh varies from lens to lens.

Another thing that took me a while to get, is that long lenses are only "sort of" better for shallow DoF for the same subject composition. There is less background due to perspective, so decreases the chance of having unwanted background, and the background is zoomed in so the blur is more apparent, but *same* level of actual detail loss. Also subjectively better for portraits due to distortion, but I personally have several portrait keepers shot at effective 24. I definitely wont be forgoing the usefulness of a more verstile faster prime (the 25mm 1.4) for the supposed portrait benefits of ~80mm. May have both one day but its really far down the list

While I have only tried 2.8 so far (the pany 12-35mm), I've found that if I just do a head, maybe a collarbone, and background is 20yrds + I can get moderate bokeh wide open. Plan to get the 25mm 1.4 soon and, as you have shown in the last photo, expect reasonable blur capabilities for head + upper body shots but probably not full body.

I just grabbed a couple of shots with the 25mm f1.4 and added them to the straight comparison series.

AngelicBeaver wrote:

averagejoe576 wrote:

I am in your exact shoes, thanks for the pics.

One thing helpful to people researching, took me a minute to get this as well, you and I are interested in "shallow DoF" more so than Bokeh, the former being how easy it is to get backround blur, and the latter being how the blur looks *if*/when you can get it. I do want it to look good if I get it (e.g. good bokeh), but the main struggle is just to get human subject + background blur at all.

So if you search '[lensName] bokeh' its correct to expect to see the macro object shots, since they show the bokeh the best. I think the reason serious reviews don't do many shallow dof examples is they expect enthusiasts to know this behavior simply from the aperture, wheres bokeh varies from lens to lens.

Another thing that took me a while to get, is that long lenses are only "sort of" better for shallow DoF for the same subject composition. There is less background due to perspective, so decreases the chance of having unwanted background, and the background is zoomed in so the blur is more apparent, but *same* level of actual detail loss. Also subjectively better for portraits due to distortion, but I personally have several portrait keepers shot at effective 24. I definitely wont be forgoing the usefulness of a more verstile faster prime (the 25mm 1.4) for the supposed portrait benefits of ~80mm. May have both one day but its really far down the list

While I have only tried 2.8 so far (the pany 12-35mm), I've found that if I just do a head, maybe a collarbone, and background is 20yrds + I can get moderate bokeh wide open. Plan to get the 25mm 1.4 soon and, as you have shown in the last photo, expect reasonable blur capabilities for head + upper body shots but probably not full body.

I just grabbed a couple of shots with the 25mm f1.4 and added them to the straight comparison series.

The difference between the zoom and the better primes can be staggering. The Leica 25mm and especially the 75mm really shine here.

One of the common criticisms of the 12-40 is that even at f2.8, the bokeh can be "distant" and it's plain to see in your photos. Though bringing the subject closer to the lens will help.

I was really surprised by the difference between the 20mm and the 25mm.  I expected a bit more blur in the background, but the little bit of extra speed and 5mm really seems to make a difference.  I wonder if the less sharp edges of the 25mm are enhancing the effect.

Those are great examples.  Thanks.