85mm f/1.8 or 70-200 f/4L?

[Sheiky]

I mean both quantity and quality. Good isolation of the subject, as well as smooth blurring of the background.

Here are a few I could find in a quick search, both shot at f4:


50D with 70-200 f4L @ 100mm - f4 - 1/250 - iso-100 - subject-distance 1.4m(according to exif)





50D with 70-200 f4L @ 70mm - f4 - 1/1600 - iso-400 - subject-distance 7m(according to exif)





Both images are uncropped, so original dimensions.


Also take a look at Pixel-Peeper and use their advance search option.


Good luck, Jan

[Jon Ruyle]

I mean both quantity and quality.

Both have good quality bokeh (though neither is corrected for bokeh over sharpness).


Quantity depends on what you're shooting. If you cut subject size in half, aperture to get the same DOF doubles. I think f/4 is fine for head/shoulder portraits (esp children), though on a crop body, faster might be better. (On full frame, I sometimes stop down to f/5.6 when taking a picture of a child's head). If you're taking a picture of something really big, even f/1.2 may not be as fast as you want.


It also depends on how far back the background is. With a close background, f/1.8 will show more blur, and f/1.8 will isolate the subject better. But if the background is far enough back, 200 f/4 will actually about the same blur than 85 f/1.8 (aperture dominates as you approach infinity). Longer lenses also give anappearanceof more blur by magnifying background details.


Not simple. In short: to isolate subject, I would choose the 85. To get a creamy looking distant background while keeping the entire subject in focus, I would choose 70-200 f/4.

[Jon Ruyle]

Look at Jan two pictures taken at f/4. Notice how different the owl (small subject) looks from the two people (big subject). In the first picture, f/1.8 would have given too shallow a DOF for the tastes of many, and the blur at f/4 is already great. For the second, I think even f/1.8 would not have eliminated the background (though it would have done a better job relegating it to background status).


The second looks like it was taken with a rather short focal length... less than 200mm anyway. At 200mm there would have less background visible.

[neuroanatomist]

I mean both quantity and quality. Good isolation of the subject, as well as smooth blurring of the background.

This is critically dependent on Jon's other point, "Keep in mind that subject distance and background distance matter a *lot*."


In other words, the 70-200mm f/4Lcan give a lot of OOF blur with decent bokeh - but it's up to you as a photographer to make that happen. The70-200mm f/4L and the 85mm f/1.8 both have 8-bladed apertures, so the quality(bokeh)of OOF blur will be good. But, f/4 is generally not ideal for quantity of OOF blur. That means if you want to isolate your subject, you need some degree of physical isolation, too. Here's an example:


[img]/cfs-file.ashx/__key/CommunityServer.Components.UserFiles/00.00.00.35.15/Sparrow_2700_s-Landing.jpg[/img]


EOS 7D,EF 70-200mm f/2.8<span style="color: red;"]LIS II USM + EF 1.4x II Extender @ 280mm, 1/2000 s, f/6.3, ISO 3200


Please excuse/ignore the apparent lack of sharpness - yesterday morning was my only chance this week to get out and shoot, it was dim and there was a heavy and misty drizzle falling when I took the shot (actually, it rained the whole day [] ). Thank goodness for weather-sealed lenses and body!


My point here is that the subject is very well-isolated and the forest in the background is blurred completely out, even at the relatively narrow aperture of f/6.3. That's because the focal length is long (280mm), the sparrow was somewhat close for a bird (~25 feet, I guess), and the forest was ~60 feet behind the sparrow.


Back to the lenses in question. With the 85mm f/1.8 @ f/1.8, you can take a portrait shot a few feet from your subject with the background a couple of feet behind the subject, and get decent OOF blur. You don't have to work very hard to blur out the background. With the 70-200mm f/4, you'll need more distance between subject and background, and you'd want to be using the longest focal length you can (in the space available), and be as close to your subject as possible, all to minimize the DoF.


Here are a couple more examples I just ran across. The field of view is the same, the subject is the same (although she's in different stages of readiness for the evening out), the background is the same, and she's standing in the same place relative to the couch behind her - so, these shots are identical in terms of framing and subject-to-background distance.


[img]/cfs-file.ashx/__key/CommunityServer.Components.UserFiles/00.00.00.35.15/IMG_5F00_2569.jpg[/img] [img]/cfs-file.ashx/__key/CommunityServer.Components.UserFiles/00.00.00.35.15/IMG_5F00_2585.jpg[/img]


T1i,EF 85mm f/1.8 USM,1/100 s, f/2.2, ISO 1600 T1i,EF-S 17-55mm f/2.8 IS USM @ 33mm, 1/60 s, f/4, ISO 200


As you can see, the OOF blur is much stronger at 85mm f/2.2 (which is not even wide open for that lens). Of course, this isn't a completely fair comparison because of the different focal lengths (DoF is thinner with longer focal length for the same subject framing), however since the framing is the same, I was much closer to her with the 33mm shot on the right (DoF thinner with closer subject).


A lot of it will come down to how much room you have - if you'll be able to use the zoom at the long end for your shots and have even more room to place your subject further from the background, the 70-200 f/4L should work.


On the whole, I think that if your primary goal is portraits and you plan to shoot some of them indoors, your best bet is theEF 85mm f/1.8. One point to note, though is that to get the same benefits of that wide aperture outside you might need to use an ND filter on the prime lens (likely a 3-stop/0.9/8x).

[Sheiky]

Alright I updated my photos with exif inclusive subject-distances(never saw that one in exif before).

Notice how different the owl (small subject)

The Owl's head is about as big as John's daughters head []

looks from the two people (big subject)

You're right about that.

The second looks like it was taken with a rather short focal length... less than 200mm anyway. At 200mm there would have less background visible.

Both are. The owl is shot at 100mm and the guys are shot at 70mm. In these examples the greatest variable is probable distance to subject. 1.4m vs 7m. And also the 30mm focal difference and subject-size, which made the composition different.


I bet that a head-portrait at 70mm f4 could look pretty good and with a nicely blurred background. Keeping in mind of course that the subject-background-distance also needs some space.

I mean both quantity and quality. Good isolation of the subject, as well as smooth blurring of the background.

This is critically dependent on Jon's other point, "Keep in mind that subject distance and background distance matter a *lot*."

Roger that!


I only showed my photos to show that the 70-200 CAN produce very nicely blurred backgrounds and isolation of the subject if taken by a person who knows his/her lens.

As you can see, the OOF blur is much stronger at 85mm f/2.2 (which is not even wide open for that lens). Of course, this isn't a completely fair comparison because of the different focal lengths (DoF is thinner with longer focal length for the same subject framing), however since the framing is the same, I was much closer to her with the 33mm shot on the right (DoF thinner with closer subject).

Not even close to a completely fair comparison if you ask me [A]


I'll look for a few more examples if I have some more at f4

[neuroanatomist]

Not even close to a completely fair comparison if you ask me [img]/emoticons/emotion-13.gif[/img]

You're right. DoF at 85mm, f/2.2, and 10 feet is half the depth of 33mm, f/4 and 4 feet.


Ok, I was a little biased. [6] I just really like the 85mm f/1.8 lens. So much so that I'm planning on getting the 85mm f/1.2L II!

I only showed my photos to show that the 70-200 CAN produce very nicely blurred backgrounds and isolation of the subject if taken by a person who knows his/her lens.

I think this is the main point - bokeh (quality) of OOF blur will be similar between the 85mm f/1.8 and the 70-200mm f/4L. But, getting a good quantity of OOF blur is generally going to be easier with the 85mm f/1.8. That's probably one reason I liked the 85mm f/1.8 so much in the first place - open it up to f/1.8-2, take one step closer to your subject, and BAM - you've got good OOF blur without paying much attention to the background.


As you say, if you know your lens, you can certainly get there with the 70-200mm f/4L. Most of the time, for 'around the house' random opportunities for portrait-like shots, there's just not enough space for sufficient subject-to-background separation for f/4 to do the job. But for 'real' portraits, i.e. setting up a background, picking the right spot in a park, etc., the f/4 zoom would do nicely, I think.

[canoli]

just curious what you decided...lot of good info in this thread - from the DOF calculations to good ol' "I just like x better than y"


I'd recommend the 1.8 for one reason - budget. An "arm and a leg" is different for everyone of course but I'm guessing &lt; $600? Even with a $1000 budget I'd get the 1.8 because I would rule out the non-IS versions of the 70-200s.


The convenience of a zoom is great and all the Canon 70-200 Ls are excellent. But they're expensive. I would pass on a non-IS zoom in that range because I believe the benefits of IS are well worth the wait. Even the older 2- and 3-stop versions make a big difference.


So if budget, IQ and bokeh were my main considerations I would rule out zoom lenses.


I'd go for the ~3 more stops of light-gathering and buy the 1.8. Then when your budget allows buy one of the IS L zooms.

[Jarhead5811]

Bokeh quality is largely Dependant on composure, distance to subject vs. distance to backgroundand focal length.


[url="http://www.flickr.com/photos/jakeandmelissawright/4007150322/in/set-72157622463216523/][/url]


[b]06/24/2008[/b] XSi w/ EF 75-300mm f/4-5.6 USM II,1/500, f/8.0, 300 mm, Iso 200


If you are close enough to the subject and frame it with a distant bland background even a POS lens can get a fairly nice blur with a slow aperture.This is one of my earliest DSLR shots.


<span style="font-family: 'Arial', 'sans-serif'; color: #000000; font-size: 8pt; mso-ansi-language: EN; mso-themecolor: text1; mso-fareast-font-family: 'Times New Roman';"]


04/04/2010 XSi w/EF 70-200mm f/2.8 L USM (NON-IS), 1/3200, f2.8, 120mm, Iso 200


Reguardless between the 70-200mm f/4 L USM andthe EF 85mm f/1.8 I'd go forthe EF 85mm f/1.8 it's next on my list. (I thinkI'd get an ND filter for it in the same order to make it more usable wide open, or near it, inbright conditions.)

[realityinabox]

So, call me crazy for pulling this one (kind of) out of left field, but I saw a good deal on the 24-70L on BH and I pulled the trigger. $1049 used in good condition, 9+ on their scale, $150 less than any other used 24-70L I've seen.


I'm still not 100% sure it was a good decision, but I figured with a deal like that, I couldn't pass it up. Plus, I have 15 days to return it if it that deal was really too good to be true. We'll see.

[btaylor]

To be honest with you I think you've made a good choice. When I was using a 40D, I found even my 50mm f/1.8 a bit long for portraits and had to stand at least10m away with the 70-200mm f/4L IS to get a full body portrait.


So the 85mm f/1.8, although it's a fantastic lens, would be too long for me on a crop sensor. The 24-70mm will give you a good amount of background blur (at great quality) with some flexibility in that it's a zoom. On FF it's a dream but I haven't tried it out on the 40D since moving to FF.


The 17-55mm f/2.8 IS would have been a similarly good choice but I understand you eventually want to go FF. In that case you've made a great choice because the 24-70 is built like a tank and will last you for years.


Have fun, Ben.