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Old Jan 15, 2007, 1:21 AM   #1
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Here I go again searching for another piece of lens to buy. I am searching for a prime lens close to the perspective of our naked eye. I have the FA 50mm f/1.4 lens right now but I find it a little bit too long for a dinner table/party type lens. There are a few lens that I had my eye on.


Sigma EX DC 30mm f/1.4 about $450 shipped

I think this would be the best lens for what I am looking for but $450 is kinda pricy for what I want to buy for this lens. I am a firm believer in Sigma EX quality lens so I am assuming that this lens will live up to the EX series lens. I have 2 other Sigma EX series lens and I love them. The focal distance would be very close to our eyes that was what turned me on to this lens.


Sigma EX DG 28mm f/1.8 about $280 shipped

This was another lens that caught my attention mainly from the price. This lens is about $170 cheaper than the 30mm one above. I am not sure how big of a difference between 28mm and 30mm but I wouldn't mind having it a little bit wider. I know f/1.8 is not as bright as the f/1.4 but I am not really concern about the extra .4 stop. One of the biggest thing holding be back from buying this is the size of the actual lens. The Sigma 30mm is a DC lens so it is a little bit smaller at 62mm front compaired to 77mm front. For a walk around indoor lens, I find that kinda big, and this is what makes me want to sell my Sigma with a 82mm front!


Pentax 40mm limited f/2.8 about $280 shipped -$50MIR = about $230

I love my Pentax FA 50mm f/1.4 just kinda hate that it is a little bit too long indoors. The Pentax 40mm would work out much better and it is the limited series. The $50 rebate makes it a lot better deal too. I wish that it was a little bit brighter but I could live with f/2.8. One of the thing that I liked about this was the pancake style lens which is a big bonus when I take it traveling. The only thing that I am unsure about this lens is if 40mm is still to long for me.

At the time I am in no rush to get this lens but for the pentax I would like to have it before the rebate expire at in March. I know for the next few days I will be up all night comparing between these three lenses, reading review and looking at sample pics. If any of you have any experiance with any of these lens please shine of light on me. Or if you see any other prime AUTOFOCUS lens that I might have missed that is a good deal for the money feel free to tell me about it.

Thanks in advance.




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Old Jan 15, 2007, 12:56 PM   #2
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superakuma wrote:
Quote:
Sigma EX DC 30mm f/1.4 about $450 shipped

I think this would be the best lens for what I am looking for but $450 is kinda pricy for what I want to buy for this lens. I am a firm believer in Sigma EX quality lens so I am assuming that this lens will live up to the EX series lens. I have 2 other Sigma EX series lens and I love them. The focal distance would be very close to our eyes that was what turned me on to this lens.


Sigma EX DG 28mm f/1.8 about $280 shipped

This was another lens that caught my attention mainly from the price. This lens is about $170 cheaper than the 30mm one above. I am not sure how big of a difference between 28mm and 30mm but I wouldn't mind having it a little bit wider. I know f/1.8 is not as bright as the f/1.4 but I am not really concern about the extra .4 stop. One of the biggest thing holding be back from buying this is the size of the actual lens. The Sigma 30mm is a DC lens so it is a little bit smaller at 62mm front compaired to 77mm front. For a walk around indoor lens, I find that kinda big, and this is what makes me want to sell my Sigma with a 82mm front!
I will be watching this post to see if there are any comments on these Sigma lenses, they are significantly faster than the Pentax lenses and, in the case of the 28mm at least, not expensive.

Ira
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Old Feb 8, 2007, 2:14 PM   #3
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Any updates on this anyone?

When I posted this post I put my order in for the Pentax 40mm limited but still have no recieve it because of it being out of stock.

Another lens that I had my eye on was the Pentax FA 28mm f/2.8. This lens is the same series as the FA 50mm f/1.4 so can I assume that the picture quality would be the same or close to it?
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Old Feb 8, 2007, 3:44 PM   #4
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50mm would be "normal" on a full frame camera.

40mm is still going to convert to a bit more (60mm)

If you really want normal eye perspective then a 35mm would do it (52mm)

Really closer to 33mm but don't think anyone makes one.

Personally I find 28mm works well indoors and only slightly sub "normal" (42mm)
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Old Feb 8, 2007, 8:55 PM   #5
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50mm is only listed as a normal lens because it is about the measurement of the diagonal of a 35mm negative. Normal from a visual perspective is about a 85mm lens, since that is the magnification the human eye sees, and that is why they are used as portrait lenses.

The human eye does not see a very wide field of view, but it moves around very rapidly, which allows us to see a wide field of view when our brain puts the pieces together.

Wide angle lenses are the biggest problem we have with the APS/Half frame sensor we have since it crops the image so severely. In film a 28mm to 35mm lens was what most people used for wide angle shots without severe distortion, but with a DSLR we need to go to about a 18mm to get the same visual coverage.

If price is not object get one of the 21mm Limited prime lenses, otherwise get a 10-20 Zoom from Sigma, which is less expensive.

Tom
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Old Feb 9, 2007, 12:24 AM   #6
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I already have the sigma 10-20mm lens and I love it. But is is not as bright as what I want it to be. I am pretty much looking for a small prime lens for indoors.
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Old Feb 9, 2007, 3:08 AM   #7
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ennacac wrote:
Quote:
50mm is only listed as a normal lens because it is about the measurement of the diagonal of a 35mm negative. Normal from a visual perspective is about a 85mm lens, since that is the magnification the human eye sees, and that is why they are used as portrait lenses.
I'd disagree.... more a matter of not having to be right on top of the subject.

A 50mm on a FF camera if you look up from the VF nothing changes. (except your angle of view is wider)

While not a lot, with an 85mm it is going to look noticeably closer/larger through the VF.
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Old Feb 9, 2007, 9:10 AM   #8
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Hayward wrote:
Quote:

A 50mm on a FF camera if you look up from the VF nothing changes. (except your angle of view is wider)

While not a lot, with an 85mm it is going to look noticeably closer/larger through the VF.

If you have a zoom lens, try this: Hold camera vertical, and look through VF with right eye while keeping left eye open - adjust zoom until everything looks like normal stereo vision. Let us know what (35mm equivalent) focal length this occurs at.

I have 35mm SLR, digital zoom camera, and now *ist D, but don't have the lenses needed for *ist D yet. With the others, I get normal view at around 75-100 mm equivalent. Part of it of course, depends on the amount of reduction in the VF.

brian


edit: Re-reading OP I see it is re: perspective, not magnification. For the intended purpose of dinner table shots, you generally need wider than 'normal' lens. With my 18-35mm, I find the 24-28mm range about right for these shots.
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Old Feb 9, 2007, 3:31 PM   #9
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Well at any rate, especially with a crop camera a 50mm (I'd say even a 40mm likely) is too much for small room/space , and since that was part of the original question....

I've found 28mm works quite well, still relatively "normal" (again on a crop) with none of the distortion you start do get when you get down to say 18mm
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Old Feb 9, 2007, 4:09 PM   #10
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The answer is simple. You have a 1.5 crop from the 35mm standard. In the days of film, some people felt that the 35mm lens was the closest to the human eye, but most used the 50mm lens as normal. To get the perspective of a 35mm lens on a digital, you need a 28mm lens, for a 50mm perspective, you need a 35mm lens.
The Pentax 35mm/f2 lens is reasonably(:?) priced and purported to be very good. Your decision as to needing a 35mm perspective or a 50mm perspective is highly personal. I am using a Sigma 17-70mm lens and it seems to provide me with choice and still be sharp and flexible overall. I got it for $325 at the Camera Spot. A 28mm prime will be a bit more.
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