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View Full Version : Fisheye lenses and focal length multiplyer



sherlock
01-23-2005, 04:02 PM
Hi,

I am looking for a good wide angle lens, but with my dSLR's 1.5x focal lenghth multiplyer, even a 24mm wide angle becomes a 36mm normal lens (wide- yes, wide enough-no). If i bought a 16mm fisheye lens, and put it on my dSLR, will it still be fisheye even though it becomes a 24mm lens? Thanks!!

Andrew S.

sherlock
01-28-2005, 04:57 AM
Hi,

I can't belive that noone knows anything about this topic. I've looked all over but I can't seem to have my question answered. What about George Rheim, you seem to know everything!? Thanks anyways guys and my search continues!


Andrew S.

jeisner
01-28-2005, 05:29 AM
It will still have the distortion of a fisheye lens but not as much, obviously as it is cropping the center of the image.

I am not sure how a circular fisheye would look, it most likely wouldn't look how you want.

D70FAN
01-28-2005, 09:20 AM
Hi,

I can't belive that noone knows anything about this topic. I've looked all over but I can't seem to have my question answered. What about George Rheim, you seem to know everything!? Thanks anyways guys and my search continues!


Andrew S.

Andrew, sorry I missed your original request, and there are a ton of people on these forums who should be able to answer your question. As a side note I definatelly am not an expert on lenses, but I have tried a few and know of what is available by researching and reading. I know a lot about a little, and a little about a lot. Beyond that I am learning from the pool of experts on the DCRP, a couple of other sites, and from talking to people who make their living, either shooting, or selling , or both. And then going out and trying what I've learned.

That said.

You didn't say whether you wanted a prime or zoom, and since you are using 1.5 as the crop I assume that your camera is not a Canon. There are plenty of primes and zooms that go down to 18mm (27mm equiv.) and the 12-24 from Sigma seems to be a popular non-fish-eye lens, and they also make a 14mm f2.8 and a 15-30. Tamron and Nikon also make a 14mm f2.8 in the $1000 to $1400 range respectively. The others run in the $500 to $800 range.

Since I have not used these lenses I can't say as to their quality but for what the 14mm f2.8's cost they should be very good.

I use an 18-125 Sigma which covers the range from 27-182mm (Equiv.) nicely ($270), and again there are many lenses available in the 18mm to 20mm base zoom or prime WA range that are not fish-eye. Of course some will require a little post processing when shooting archetecture.

If you hunt the pages of B&H photo and Norman Camera you will get an idea of what's available. After that you just have to search for reviews, or better yet try the lenses at your local camera store.

Hope that helps.

sherlock
01-28-2005, 01:13 PM
Hi,

The reason for my post is that I want a prime lens, one that focuses much closer than the zoom lenses out there today which can only focus down to 38cm (on the nikon 18-70 dx). For landscape photography, 38cm is not good, especially if you have a great composition with flowers in the foreground and a mountain range in the background. I know that there are ways of getting the shot without a close focusing lens, but it's much easier if you have one. BTW thanks so much for your input!

Andrew S.

D70FAN
01-28-2005, 02:21 PM
Hi,

The reason for my post is that I want a prime lens, one that focuses much closer than the zoom lenses out there today which can only focus down to 38cm (on the nikon 18-70 dx). For landscape photography, 38cm is not good, especially if you have a great composition with flowers in the foreground and a mountain range in the background. I know that there are ways of getting the shot without a close focusing lens, but it's much easier if you have one. BTW thanks so much for your input!

Andrew S.

So now I'm a little confused (not really that unusual these days). So what you really want is a wide angle lens that can focus down to, say, 7-10 inches (16mm to 26mm). Right?

So now I think I'm beginning to see your problem, as you need a wide angle macro/micro lens.

The widest "macro" lens I have seen is the Sigma 24mm f1.8 EX DG Aspherical Macro.

The Sigma 12-24 (around $670) that I mentioned earlier might work as it has a minimum focus distance of 28cm. While not a true macro/micro class lens it is very close.

The comments I've seen and heard on this lens have been very positive, but again I've never used it. Although after reading the reviews maybe I will give it a shot this weekend.

sherlock
01-28-2005, 02:54 PM
Hi George,

I'm sorry that my posts were too vague, but yes, I want a wide angle macro. But you do see my point that even high quality zooms just don't focus down close at all. Also, thanks so much for your input, it really helped. I have another completely off topic question, I want to post photographs on some of my posts, and I know that I have to convert the jpeg image to a lower file size, but I can't seem to find how to do this. Thanks so much!!!


Andrew S.

D70FAN
01-28-2005, 03:41 PM
Hi George,

I'm sorry that my posts were too vague, but yes, I want a wide angle macro. But you do see my point that even high quality zooms just don't focus down close at all. Also, thanks so much for your input, it really helped. I have another completely off topic question, I want to post photographs on some of my posts, and I know that I have to convert the jpeg image to a lower file size, but I can't seem to find how to do this. Thanks so much!!!


Andrew S.
Most image processors (Photoshop, Piantshop Pro, and even Irfanview) have a image sizing function. You will have to play with it to get the picture down to 40K. I typicaly use 640 x 480 and save (as a separate image) at medium JPEG. this assumes a starting file size of around 2.5MB.

After that you simply upload and insert using the manage attachments at the bottom of the page and the image insert in the toolbar.

Another way to post is by using a hosting service, uploading, and then directing viewers to those pictures. I use smugmug, but there are free sites available as well.

sherlock
01-28-2005, 04:43 PM
Hey George,

Thanks a lot, I think that I finally got it. This photograph was taken in Nova Scotia, in Peggy's Cove. I took many photographs but this is one of my favorites. I don't think that the photo will come up in very good resolution, as I had to pare down to 320x240 to get the file small enough.


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D70FAN
01-29-2005, 05:42 AM
Hey George,

Thanks a lot, I think that I finally got it. This photograph was taken in Nova Scotia, in Peggy's Cove. I took many photographs but this is one of my favorites. I don't think that the photo will come up in very good resolution, as I had to pare down to 320x240 to get the file small enough.


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Yup. You have mastered the DCRP! :)

Have fun.