Focal Length and DOF Blurring

[William W]

Good.

Also notice how, not only does the Bokeh (characteristic) differs between the two lenses, but the EXPOSURE PARAMETERS are different between the two shots. In the second shot (the Telephoto Zoom) the BACKGROUND is little bit 'MORE EXPOSED’ (i.e. 'brighter').

You might like that shot as 'better bokeh' compared to the other shot - but we must also note what we are seeing (as well as the lens' bokeh differences) is also the result of the different light, on the background.

***

Also even though the Depth of Field is the same for both shots - the background will appear "slightly different" that is PERSPECTIVE.

To make the SAME FRAMING, we have to step farther away from the Subject when we use a longer lens -= so COMPARATIVELY the ratio of Camera to Subject :: Subject to Background changes.


WW

[DennisS]

Thanks Bill - all good information.

You may find this link interesting - I did as I like to get into technicalities...!!!

http://lewiscollard.com/technical/background-blur/

http://photographersconnection.com/h...rounds-blurry/

[William W]

Thank you for the links.

Have a great weekend.

WW

[pnodrog]

Have you considered getting a Nikon 60mm f/2.8 AF-S Micro-Nikkor and using a soft patterned or plain painted backdrop(s). The lens is fast enough and sharp enough for what you want and gives an equivalent of 80mm(oops 90) on a DX camera. You also get the benefit of using it for macro work.

[DennisS]

Actually I may have missed that, maybe due to it being macro - that is a great lens - f/2.8 with rounded 9 blade diaphragm and will provide 90mm coverage on my DX body. It is within my budget and will work great for portraits as well as macro work. It is on my wish list for now, as it would certainly round out my lens capabilities to include macro. In any case, after reading all the posts, it appears just getting a new lens will not provide me anything more than I already have. If I were to make a decision on this lens, it would be mostly for the macro capabilities.

Thank you for bringing this to my attention - I believe I will probably eventually get it.

[pnodrog]

I am not sure you should take any notice of someone that could not multiply 60x1.5 ooops but I know of a number of photographers who use it for portraiture on a DX body.

[xpatUSA]

Have you considered getting a Nikon 60mm f/2.8 AF-S Micro-Nikkor and using a soft patterned or plain painted backdrop(s). The lens is fast enough and sharp enough for what you want and gives an equivalent of 80mm(oops 90) on a DX camera. You also get the benefit of using it for macro work.

For several years, I used that very same lens for close-up work and it certainly exceeded the capabilities of the D50 I bought it for.

It is a very well-regarded lens, see:

http://slrgear.com/reviews/showprodu...ct/1175/cat/12

Do note that it is only f/2.8 at infinity, though.

[jcuknz]

[QUOTE=xpatUSA;337500Do note that it is only f/2.8 at infinity, though.[/QUOTE]

If by this you mean the aperture gets smaller as it focuses closer .. does this matter? Because as the focal length gets longer as you focus closer the DoF reduces It is only a 60mm lens when focused at infinity I think. at double extension it is a 120mm lens.

[xpatUSA]

Do note that it is only f/2.8 at infinity, though.

If by this you mean the [effective] aperture gets smaller as it focuses closer .. does this matter?

It certainly didn't matter to me and no criticism of the lens was intended. The Nikon D50 reported the effective aperture just fine.

The link I gave and which I assume that you read, does actually say:

The lens is marked as a constant ƒ/2.8 lens, but in fact the effective aperture will be smaller as you focus at shorter and shorter distances. The following table lists the aperture-to-distance differences:

Subject distance	6''	7''	8.5''	9''	10''	1' 3''	3'	infinity
Largest aperture	ƒ/4.8	ƒ/4.0	ƒ/3.8	ƒ/3.5	ƒ/3.3	ƒ/3.2	ƒ/3.0	ƒ/2.8
Smallest aperture	ƒ/57	ƒ/51	ƒ/45	ƒ/45	ƒ/40	ƒ/36	ƒ/36	ƒ/32