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.

[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).

[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.

[Sheiky]

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

Great deal!


Now you've managed to do 2 things...and get a good lens for portraiture and get a great general-purpose lens to replace your sigma and a small benefit: it's usable on FF as well []


Great one! Enjoy it as much as you can!

[canoli]

Excellent move! If you've never bought used from B&amp;H before you're in for a nice surprise. When they rate something 8+ or above it is very hard to tell it's a used item. Close inspection, sure. But at a glance and to any casual observer it'll look new. And as you noted, 2 weeks to return, no questions asked, full refund. God I love that store!


This was a 9+? Fuggedaboutit - it'll look brandy new. []


The 24-70 has one of the best reputations of any lens out there short of the Leica glass, which of course is (at least) 4x as expensive!


With the IQ of that lens, even wide open, and a new-ish body you'll be able to shoot 1600 in low light no problem; not have to worry about under-exposing and getting overly noisy images. I know you said low-light wasn't a consideration as you work with strobes but you'll be happy to have the option anyway.


Congratulations!

[Keith B]

24-70 is my most used lens. You can also catch Annie Leibovitz shooting with it quite often (when she is shooting her 1Ds).