Is 6.3 enough for bokeh?(for 600m)

[mikoh4792]

I'm looking at a few budget super telephotos(namely tamron) and am wondering if 6.3 is enough at that focal length to create nice bokeh.(I'll be shooting birds at no more than 100 feet away, and probably at 30-50 feet away most of the time).

Also would that be too slow for shooting a little after sunrise?(when the light is starting to come out).

If not, maybe I should go with a tamron 70-200 2.8 or nikon 70-200 f4 with teleconverters.

 

[480sparky41 41]

Aperture is but one variable to bokeh. The focal length used, the focus distance and the build of the aperture blades (shape and number of) all factor into the equation.

"Too slow" may depend on the camera you're using, and how much noise you're willing to accept.

If you start using teleconverters, you're going to lose lens speed as a function of the TC. The 70-200/2.8, with a 2x TC, will be a f/5.6 lens.... not too far from 6.3.

 

[mikoh4792]

Aperture is but one variable to bokeh. The focal length used, the focus distance and the build of the aperture blades (shape and number of) all factor into the equation.

"Too slow" may depend on the camera you're using, and how much noise you're willing to accept.

If you start using teleconverters, you're going to lose lens speed as a function of the TC. The 70-200/2.8, with a 2x TC, will be a f/5.6 lens.... not too far from 6.3.

Thanks. I will be using a nikon d7100 body and am looking at the Tamron 150-600mm(9 blade circular aperture). I will most likely be shooting at the longer end (400-600).

 

[coastalconn]

Your "Bokeh" will have more to do with the distance of your subject vs the background. If you want to know what the Tamron 150-600 and D7100 are capable of, I have a rather large database of images that I have taken with that combo... Flickr Search tamron 150 600 d7100

 

[Mr.Photo]

As mentioned above, aperture is only one part of the equation for blurring out the background. With long telephoto lenses subject to background distance as well as the distance from the lens to the subject play a larger role as the depth of field even if using a fast aperture, is much larger at longer distances.

Here is a shot I took with my Tamron 70-300 VC at F8 to demonstrate what can be done and how to achieve it. Here I was approximately 12-15 feet from the feeder with the zoom at 300mm. Even at f/8 I was still able to blow out the background as the depth of field was quite small at that distance.

DSC_4340 by Gary C's Photography, on Flickr

 

[AKUK]

I'd suggest just sticking with the Tamron. Attaching a x2 TC on a Nikon 70-200mm f/2.8 will give you 140-400mm f/5.6 and only 1/3 stop brighter than the Tamron. The trade off is 200mm in focal length, which is nothing to be sniffed at. The only thing you may struggle with is focus in low light but the D7100 has a pretty good AF system and should be okay.

 

[ruifo]

It works, even with higher f/#.
Test it here, in this "Online Depth of Field Calculator".

 

[KmH]

As mentioned it's about more than just the lens aperture.
f/6.3, 500 mm , about 75 feet to point of focus.
Notice how the the blur increases with distance behind the bird.

 

[mikoh4792]

Got it thanks guys. My 150-600 is arriving next morning. I'll see what I can do with it.