D40x - fast lens needed

I am thinking of getting a D40x as a travel body. I have a 18-200 VR lens which

I will use for most photography. But, I also want to bring a fast lens for low

light photography and for times when I want to blur the background very much.

 

I have a Nikon 50mm f/1.4, but as I understand it, this lens will not autofocus

or meter with the D40x.

 

Can anybody recommend a fast lens (f/2.8 or faster) that will autofocus and

meter with the D40x?

 

Thanks.

Sigma 30/1.4.

 

Sigma 70/2.8.

 

(may be) some other Sigma primes.

I have a sigma 30/1.4 on mine. Great combination.

Thanks Warren and Vivek. Am I correct in assuming these are full frame lenses so with the crop factor, I will have the equivalent of a 45mm lens on a 35mm film camera body?

Josh,

 

The two lenses I mentioned are infact DX lenses.

 

Don't worry about the 30 'becoming' a 45 and all that. Yes, the 30/1.4 will be a 'normal' lens on your D40x.

 

The Sigma 30/1.4 is really an impressive lens. I wish many of the Nikon lenses would perform like it optically.

It is a common misunderstanding that the focal length somehow is different for a DX lens and a non-DX lens. This is the result of constant comments like "50mm becomes 75mm". A 50mm lens is always a 50mm lens regardless of what format it is designed for -- what changes is the FOV.

"... but as I understand it, this lens will not autofocus or meter with the D40x"

 

If the 50/1.4 is an AF or AF-D, then it WILL meter with the D40x, and work in all exposure modes. But you are correct in that it will not autofocus.

Vivek, exactly which Sigma 70mm f2.8 are you referring to? I am aware of one that is a macro lens. Is that an HSM (AF-S equivalent)? If not, there is no AF on the D40x.

the 30/1.4 is the fastest lens you can get that will AF with a d40/d40x.

 

sigma also makes the 18-50/2.8 EX HSM (make sure it's this version) and the 50-150/2.8 EX HSM, as well as the 70-200/2.8 EX HSM. if you go to their website, they tell you exactly what will and wont work w/ d40/d40x.

 

over in nikon land, your fast lens choices for d40/d40x are more limited: 17-55 DX, 70-200 VR, 105 VR macro. there's also the $4k 200mm/2 and the $4,500 300/2.8.

 

i'd go with the sigma 18-50 or 30/1.4 if i were you.

Shun, Good point. No, this lens will not do AF with the D40x. Not a HSM lens. The one you allude to is the Nikon 105/2.8 AFS VR. That is fully compatible with the D40x.

 

Only lens that is fully compatible is the 30/1.4 and not the 70/2.8.

The Nikkor 17-55mm f/2.8 AF-S ED-IF DX lens is sweet. I use it on my D40x.

Anthony, I understand that the focal length of the lens does not change. That is why I referred to the "crop factor". What I want is a lens that gives me the same field of view on the D40x that I would get with a 50mm lens on a 35mm film body like an F100. And, of course, fast enough for low light level work and to throw the background out of focus. Out of focus backgrounds seem to be a lost art to many who only know the cheap, slow consumer zooms.

The 30/1.4 will give you a 45/1.4. A few steps in either direction will give you a bit of a zoom. The colors are sharp, the lens focuses quickly and the weight balances nicely on the d40x body. The background, at 1.4 is creamy smooth and the depth of field is appropriately shallow. It has become my favorite lens, reminds me of shooting with a rangefinder.

"Out of focus backgrounds seem to be a lost art to many who only know the cheap, slow consumer zooms."

 

It is also an issue with focal lengths and formats. Shorter lenses used on smaller formats simply do not behave the same as longer focal lengths on larger formats -- even at the same or comparable apertures. However, if you take a step or two or three back with the smaller format with the same focal length, you will get the same effect (with a different perspective) as you would get with a larger format using the same focal length.

"The 30/1.4 will give you a 45/1.4."

 

Since you insist on perpetuating "30mm becomes 45mm" based on format, the least you can do is get the aperture right too since an f/1.4 on film or FX "becomes" f/2 on DX format if you are measuring the DOF. If this is all too complicated, then good; just call it a 30mm f/1.4 with a smaller or larger FOV depending on the format.

Get Sigma 30mm F 1.4 unless you have a lot of cash and luck to get Nikon 28mm f 1.4.

While the terminology may be confusing, the main point, unless I get this wrong, is that the 30mm f/1.4 Sigma will give me more light through the lens and less depth of field than say a slow zoom lens with a maximum aperture of f/3.5. And that is what I am looking for.

Does anybody know a of a good discussion on how the same lens differs when used on a DX and and FX body? I am referring to how the format difference effects the depth of field and the 'perceived' focal length. Something in layman's terms would be appreciated.

I agree with Arnold above. Sigma 30mm f1.4 HSM or Sigma 18-50mm f2.8 HSM.

 

 

Kent in SD

Get a 35/2 AF-D & an 85/1.8 AF-D and focus manually...maybe add a 50/1.8.

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I ordered one of the new Cosina/Voigtlander 58/1.4 lenses to use on my D40. I'll try to write a user report after I actually use it.

"Does anybody know a of a good discussion on how the same lens differs when used on a DX and and FX body? I am referring to how the format difference effects the depth of field and the 'perceived' focal length. Something in layman's terms would be appreciated."

 

It is terms like "perceived focal length" that are in one form or another repeated so often that people start thinking 30mm looks just like 50mm when you change formats. However, even when accounting for FOV, DOF, and perspective the two focal lengths have different optical properties which are most apparent in how out of focus portions of a scene are rendered. Basically, the CoC (circle of confusion) outside of the acceptable DOF grows faster on a longer focal length than it does on a shorter focal length, which contributes to a more pleasing bokeh from longer focal lengths than what is attainable with shorter focal lengths.

 

For a comprehensive set of calculators you can go here: http://www.tawbaware.com/maxlyons/calc.htm and input various focal lengths and formats and it will give you the FOV and DOF (using different calculators) and you will see that if you stand in the same spot with a DX format and a 30mm lens you will get the same DOF one stop wider than with an FX format and a 45mm lens.

I put the 30/1.4 on my F2 and the image circle just clips on the corners without its hood. With its hood, it should cover the 5:4 frame in D3 at infinity and at f/1.4.

 

What a joy to see the images through F2's finder! I made a few snaps at f/1.4. Will look at it after developing the roll.

 

Those lucky owners of the 28/1.4 Nikkor would rejoice using it on the D3!

I have been giving this a lot of thought and I think I may have created a bigger problem than it need be. The 50mm f/1.4 will meter correctly on the D40x and that is my biggest concern. Such a large aperture lens makes manual focusing very easy, I did it for years with my old Minolta SRT 101.

 

Buying a new lens is quite expensive. Not only is there the price of the lens to consider, but also the cost of good filters. I would need at least two - a UV to protect the lens and a good polarizer. That is at least another $120 above the price of the lens. Add in shipping and my new lens is a $600 investment. I already have everything I nee for the 50mm lens. Hmmm... Manual focus is looking very good right now. :)

A couple of things:

 

1. The D40x is no Minolta SRT. Manual focusing with the 50/1.4 would be very frustrating- to say the least. Since you already own the lens, you should know that by now.

 

2. I would not (an I do not) use any filters on the Sigma lens. Keep the hood on all the time for 'protection'.

 

Filters will only crap up the images.

Josh, If you are planing to do MF on your D40x I recommend to use a Katz Eyes focusing screen for that purpose. I am using one on mine and I am very pleased.