Cascades - not so much (1 Viewer)

I have had the Cascades out for about 3 hrs now, comparing them to the PMs and the ZRs. I agree with Frank that they are nice ergonomically, they are bright and for the detail that they show, it is nice. However, in comparison to the PMs & ZRs, they just don't quite stand up to the challenge. The FOV is obviously much smaller and although all 3 pairs are 8x's, my perception is that the magnification is MUCH smaller. Does a smaller FOV mean that magnification will automatically be smaller as well? This may seem to be a stupid question to some of you; for that I apologize ahead of time. Actually, I had my Ranger SRT's out as well and I know all 4 have different FOVs, but I would expect all to show the same magnification since they are all 8xs. Be patient with the unlearned!

Clarity is good, but both the PM and the ZR obviously have a larger FOV & what I perceive to be much greater magification and clarity. Clarity & resolution - what would be the differences between these 2 in layman's binocular speak?!

I think it was Jeff that trying to decide between the Cascades and the ZRs or the PMs - I would hands down go with the ZR or PM. I have to agree that the view is nice for the price, but I think it worth the extra $ to get a larger FOV, increased clarity, contrast, etc. I did notice as I was looking at a Kestrel ,that when I viewed it through the Cascades, I noticed a yellowish cast to its breast (this was about 1pm) that I did not notice with the other two. When I tried the Cascades on the same bird but from a slightly different angle, the yellowish cast was not really noticable.

Not that I need another pair of 8x's, but I was getting prepared to have to talk myself out of keeping the Cascades. No need, my money will be better directed towards a scope. There just wasn't enough love for the Cascades!!|=(|

Scopes is a more dangerous game. They are harder to get rid of. Get a pretty good one, no alphas needed, to start with. Nikon and Pentax have ED scopes.

I think Steve C had recommended the Stokes Sandpiper. I was also considering the Nikon 50 ED after reading many posts on it in the scopes forum. A friend wants to sell me her Pentax, but it is not ED and I can't remember the model now.

Laura

That's an interesting observation. For one thing it is a commonly stated item that a porro binocular image seems smaller than the same in a roof. I think also that an 8x image sitting in a 426' fov of the ZEN might seem to seem smaller than the same thing in the nearly 2* less field of the Cascade. But you see what you see. I don't have enough experience with the Cascade, just a couple of in store quick looks, to really say. Also our genetically inherited optical systems some times mesh less well with some mechanical systems than with others. Another try before you buy reason.

Well, the stores have limited brands, so the return policy is the next best match to the try before buying idea. I returned plenty, and one I should have after a week but did not.

Steve, I may not correctly understand the FOV / image size relationship!! Perhaps I am being literal in my interpretation (and very simple!), but I thought that a smaller FOV meant that you simply did not get as wide of view, but that the image magnification was ultimately the same. Like I get 2 feet more on each side of a duck or 2 feet less on each side, but the duck stays the same size. Don't laugh at me please!!! Actually all of you will probably find this highly amusing, sad but true!

You're right. What I meant is simply that the same bird at the same magnification takes up a larger percentage of the area of a smaller field of view than it does in a larger field of view. So simply as a matter of proportion, it has a possibility of seeming larger in a smaller field, simply because it takes up a larger proportion of the field. But that is simply a perceptual thing. Looking at a bird for detail depends on image characteristics more than fov.

Objective spacing is the main cause for the illusion of lower magnification in Porros, which typically have wider objective separation than roofs. It's been discussed here and other places. Differences in FOV have a modest effect in comparison.

Thanks Steve & Henry. I am happy knowing I am on the right track! Thats why I said it was my perception. I have read the many posts on optics through the forum and I admit most are above my head - the level of knowledge regarding optics on this site is truly amazing! However, I read to learn and as I use my bins, I try to keep in mind what I have read. Whatever the reason, the Cascades are not my bin of choice, unfortunately!!

henry link said:

Differences in FOV have a modest effect in comparison.

Click to expand...

I've been puzzling over this, Henry. If you have, say, two 8x40 bins, they both have the same 5mm exit pupil. If the first has a 5° FOV and the second a 10° FOV, then the second has to squeeze in four times as much stuff (?) into the same real estate, doesn't it? So any object in the first bin should be four times as big. Shouldn't it? Where am I going wrong?

Michael

MacGee said:

I've been puzzling over this, Henry. If you have, say, two 8x40 bins, they both have the same 5mm exit pupil. If the first has a 5° FOV and the second a 10° FOV, then the second has to squeeze in four times as much stuff (?) into the same real estate, doesn't it? So any object in the first bin should be four times as big. Shouldn't it? Where am I going wrong?

Click to expand...

Object size is controlled only by the magnification (though some interesting perceptual illusions can cause some interesting problems) i.e. the angle the object subtends seen through the bins is the magnification times the object subtends seen with the naked eye.

How "many" objects you see is controlled by the size of then FOV.

Imagine looking at a horizon with a tower with your naked eye: quite a big view at 1x magnification and the tower sits in the middle of it.

Then you look at the same scene through a paper tube: much narrower view but the tower is still the same size because the magnification hasn't changed.

The paper tube changes the FOV and not the magnification. The same thing happens in binoculars. They're two independent parameters.

Note that the apparent FOV is related to both the FOV and the magnification (the crude approximation that only works for FOV < 5 degrees is AFOV = FOV * magnification).

The exit pupil is a different thing entirely. It's just a disk that all the light passes through after exiting the ocular lens e.g. the exit pupil is afocal for the target of interest but it is an image of the entrance pupil. So there is no "more" to squeeze into it. The thing that does change with FOV (or more correctly AFOV) is the angle at which the light rays converge into that disk then diverge out of the disk.

Another point not mentioned above, in addition to the roofs versus porros illusion, is larger FOVs in both roofs and porros can appear to make the magnification seem larger than it really is. This is another optical illusion but one that helps to sell binoculars!

The clarity versus sharpness issue is one I've talked about here before. Porros do seem to be more "transparent" or less "hazy". There is a quality of the image that seems different especially in less than top quality image bins. I still can't quite put my finger on what it is but I know it when I see it.

Everyone else has pretty much chimed in with all of the correct info so I don't have anything else to add on your perceptions of image size going from one bin to the next. I do often find myself noticing much the same because of the objective spacing and the field of view/proportion issues. I am surprised about the yellow color you noticed in the Cascades. I did not perceive that and I consider myself fairly sensitive to color casts in optics.

On a related note, if you are looking for a scope, you may want to take a look at that special deal over at Eagle Optics. They have an unbadged 80 mm model on sale for $200. It supposedly would retail at $500 if it were badged....at least that is how I interpreted it. I have one of the angled models on order and expect it any day now. More to follow.....

Thanks so much for all of the information everyone. Again, I amazed at the level of knowledge on the forum.

Frank, I noticed the yellowish cast only briefly and I checked it out with all 3 bins again before I changed my location. Once I changed location, I didn't notice the coloration. I will take a look at the scope. Let me know what you think of it when you get it. Thanks for all of your help, by the way!

Laura,

I just received email notification. I should have it on Thursday.